Father James Cullen, S. J., was born on April 19th 1867 at Drogheda in Ireland. At first he was educated privately, then by the Christian Brothers. Next he went to Trinity College, Dublin, to study pure and applied Mathematics. Afterwards he was in business for a while, but after a short period at an apostolic school in Ireland to learn Latin he entered the noviceship of the English Jesuit at Manresa House, Roehampton, London, as he had decided to become a priest. From 1892 till 1895 he was at Manresa in the noviceship and then for a year's study. From 1895 till 1897 he studied philosophy at the Jesuit house for philosophical studies at St Mary's Hall, Stonyhurst in Lancashire. From 1897 till 1901 he studied theology at the theologate of the English Jesuits at St Beuno's College in North Wales. He was ordained priest at St Beuno's College on July 31st 1901. In 1902 and 1903 he taught Mathematics to young Jesuits who had finished their noviceship at Manresa House. In 1905 he taught Mathematics at the Jesuit boarding school Mount St Mary's College in Derbyshire. It is said that he found difficulty in teaching. In 1906 he was sent to Stonyhurst College, also a boarding school, as accountant and later manager of the College farm and estate. Meanwhile he kept in touch with leading mathematicians and contributed articles to Nature, the Mathematical Gazette and the Messenger of Mathematics. In 1921 he left Stonyhurst and was appointed to supervise accounts of other English Jesuit houses. He died on December 7th 1933.
Where he writes:
When we searched the literature for references to Cullen numbers, we were intrigued by the fact that almost nothing could be found about Cullen as a person. Even mathematical or encyclopaedic dictionaries usually giving such information failed to disclose Cullen's complete first name or to mention the year of his birth or his death. Only the abbreviation "S.J." placed after his name in a footnote to the article