25811721408 has 56 divisors (see below), whose sum is σ = 74502020160. Its totient is φ = 7821733120.

The previous prime is 25811721361. The next prime is 25811721449. The reversal of 25811721408 is 80412711852.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6108618 + ... + 6112841.

Almost surely, 2^25811721408 is an apocalyptic number.

It is an amenable number.

25811721408 is an abundant number, since it is smaller than the sum of its proper divisors (48690298752).

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

25811721408 is a wasteful number, since it uses less digits than its factorization.

25811721408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12221485 (or 12221475 counting only the distinct ones).

The product of its (nonzero) digits is 35840, while the sum is 39.

The spelling of 25811721408 in words is "twenty-five billion, eight hundred eleven million, seven hundred twenty-one thousand, four hundred eight".