261907187581872 has 210 divisors, whose sum is σ = 885035188690668. Its totient is φ = 74830624860096.

The previous prime is 261907187581847. The next prime is 261907187581883. The reversal of 261907187581872 is 278185781709162.

261907187581872 is a `hidden beast` number, since 26 + 1 + 9 + 0 + 7 + 18 + 7 + 581 + 8 + 7 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a self number, because there is not a number n which added to its sum of digits gives 261907187581872.

It is an unprimeable number.

It is a polite number, since it can be written in 41 ways as a sum of consecutive naturals, for example, 228554178 + ... + 229697249.

Almost surely, 2^{261907187581872} is an apocalyptic number.

It is an amenable number.

261907187581872 is an abundant number, since it is smaller than the sum of its proper divisors (623128001108796).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261907187581872 is an equidigital number, since it uses as much as digits as its factorization.

261907187581872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 458251467 (or 458251439 counting only the distinct ones).

The product of its (nonzero) digits is 189665280, while the sum is 72.

The spelling of 261907187581872 in words is "two hundred sixty-one trillion, nine hundred seven billion, one hundred eighty-seven million, five hundred eighty-one thousand, eight hundred seventy-two".