25649978940 has 96 divisors (see below), whose sum is σ = 80060386560. Its totient is φ = 6817670208.

The previous prime is 25649978897. The next prime is 25649979007. The reversal of 25649978940 is 4987994652.

25649978940 is a `hidden beast` number, since 2 + 56 + 499 + 7 + 8 + 94 + 0 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 88419 + ... + 243141.

It is an arithmetic number, because the mean of its divisors is an integer number (833962360).

Almost surely, 2^25649978940 is an apocalyptic number.

25649978940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 25649978940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40030193280).

25649978940 is an abundant number, since it is smaller than the sum of its proper divisors (54410407620).

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

25649978940 is a wasteful number, since it uses less digits than its factorization.

25649978940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155048 (or 155040 counting only the distinct ones).

The product of its (nonzero) digits is 39191040, while the sum is 63.

The spelling of 25649978940 in words is "twenty-five billion, six hundred forty-nine million, nine hundred seventy-eight thousand, nine hundred forty".