25661615904 has 72 divisors (see below), whose sum is σ = 73233315792. Its totient is φ = 8523619200.

The previous prime is 25661615893. The next prime is 25661615933. The reversal of 25661615904 is 40951616652.

25661615904 is a `hidden beast` number, since 2 + 56 + 6 + 1 + 6 + 1 + 590 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

It is a self number, because there is not a number n which added to its sum of digits gives 25661615904.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 75922 + ... + 238929.

It is an arithmetic number, because the mean of its divisors is an integer number (1017129386).

Almost surely, 2^25661615904 is an apocalyptic number.

25661615904 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

25661615904 is an abundant number, since it is smaller than the sum of its proper divisors (47571699888).

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

25661615904 is a wasteful number, since it uses less digits than its factorization.

25661615904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 315150 (or 315139 counting only the distinct ones).

The product of its (nonzero) digits is 388800, while the sum is 45.

The spelling of 25661615904 in words is "twenty-five billion, six hundred sixty-one million, six hundred fifteen thousand, nine hundred four".