261657623427265 has 16 divisors (see below), whose sum is σ = 342422440012800. Its totient is φ = 190778216571072.

The previous prime is 261657623427257. The next prime is 261657623427287. The reversal of 261657623427265 is 562724326756162.

It is not a de Polignac number, because 261657623427265 - 2³ = 261657623427257 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 261657623427197 and 261657623427206.

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, 25477854985 + ... + 25477865254.

It is an arithmetic number, because the mean of its divisors is an integer number (21401402500800).

Almost surely, 2^{261657623427265} is an apocalyptic number.

It is an amenable number.

261657623427265 is a deficient number, since it is larger than the sum of its proper divisors (80764816585535).

261657623427265 is a wasteful number, since it uses less digits than its factorization.

261657623427265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50955720336.

The product of its digits is 304819200, while the sum is 64.

The spelling of 261657623427265 in words is "two hundred sixty-one trillion, six hundred fifty-seven billion, six hundred twenty-three million, four hundred twenty-seven thousand, two hundred sixty-five".