261156100465 has 16 divisors (see below), whose sum is σ = 340835571216. Its totient is φ = 190944288000.

The previous prime is 261156100441. The next prime is 261156100507. The reversal of 261156100465 is 564001651162.

It can be written as a sum of positive squares in 8 ways, for example, as 14773916304 + 246382184161 = 121548^2 + 496369^2 .

It is not a de Polignac number, because 261156100465 - 2¹³ = 261156092273 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19883466 + ... + 19896595.

It is an arithmetic number, because the mean of its divisors is an integer number (21302223201).

Almost surely, 2^261156100465 is an apocalyptic number.

It is an amenable number.

261156100465 is a deficient number, since it is larger than the sum of its proper divisors (79679470751).

261156100465 is a wasteful number, since it uses less digits than its factorization.

261156100465 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39780180.

The product of its (nonzero) digits is 43200, while the sum is 37.

The spelling of 261156100465 in words is "two hundred sixty-one billion, one hundred fifty-six million, one hundred thousand, four hundred sixty-five".