261784117 has 16 divisors (see below), whose sum is σ = 309184000. Its totient is φ = 221523120.

The previous prime is 261784111. The next prime is 261784141. The reversal of 261784117 is 711487162.

261784117 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 261784117 - 2¹⁵ = 261751349 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261784111) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22267 + ... + 31927.

It is an arithmetic number, because the mean of its divisors is an integer number (19324000).

Almost surely, 2^261784117 is an apocalyptic number.

It is an amenable number.

261784117 is a deficient number, since it is larger than the sum of its proper divisors (47399883).

261784117 is an frugal number, since it uses more digits than its factorization.

261784117 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9761 (or 9747 counting only the distinct ones).

The product of its digits is 18816, while the sum is 37.

The square root of 261784117 is about 16179.7440338220. The cubic root of 261784117 is about 639.7069923392.

It can be divided in two parts, 261 and 784117, that added together give a triangular number (784378 = T₁₂₅₂).

The spelling of 261784117 in words is "two hundred sixty-one million, seven hundred eighty-four thousand, one hundred seventeen".