2561625561564 has 36 divisors (see below), whose sum is σ = 6698503626360. Its totient is φ = 824431214880.

The previous prime is 2561625561527. The next prime is 2561625561589. The reversal of 2561625561564 is 4651655261652.

2561625561564 is a `hidden beast` number, since 2 + 5 + 6 + 1 + 6 + 25 + 56 + 1 + 564 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a self number, because there is not a number n which added to its sum of digits gives 2561625561564.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1226831122 + ... + 1226833209.

Almost surely, 2^{2561625561564} is an apocalyptic number.

It is an amenable number.

2561625561564 is an abundant number, since it is smaller than the sum of its proper divisors (4136878064796).

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

2561625561564 is a wasteful number, since it uses less digits than its factorization.

2561625561564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2453664370 (or 2453664365 counting only the distinct ones).

The product of its digits is 12960000, while the sum is 54.

The spelling of 2561625561564 in words is "two trillion, five hundred sixty-one billion, six hundred twenty-five million, five hundred sixty-one thousand, five hundred sixty-four".