12565561311 has 24 divisors (see below), whose sum is σ = 18327738000. Its totient is φ = 8295219072.

The previous prime is 12565561291. The next prime is 12565561313. The reversal of 12565561311 is 11316556521.

12565561311 is a `hidden beast` number, since 1 + 2 + 5 + 65 + 561 + 31 + 1 = 666.

It is not a de Polignac number, because 12565561311 - 2¹⁵ = 12565528543 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12565561313) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2409675 + ... + 2414883.

It is an arithmetic number, because the mean of its divisors is an integer number (763655750).

Almost surely, 2^12565561311 is an apocalyptic number.

12565561311 is a deficient number, since it is larger than the sum of its proper divisors (5762176689).

12565561311 is a wasteful number, since it uses less digits than its factorization.

12565561311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7783 (or 7780 counting only the distinct ones).

The product of its digits is 27000, while the sum is 36.

It can be divided in two parts, 125655 and 61311, that added together give a triangular number (186966 = T₆₁₁).

The spelling of 12565561311 in words is "twelve billion, five hundred sixty-five million, five hundred sixty-one thousand, three hundred eleven".