25791721816 has 32 divisors (see below), whose sum is σ = 55598941440. Its totient is φ = 10987401888.

The previous prime is 25791721801. The next prime is 25791721829. The reversal of 25791721816 is 61812719752.

It is a self number, because there is not a number n which added to its sum of digits gives 25791721816.

It is a congruent number.

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, 1369590 + ... + 1388293.

It is an arithmetic number, because the mean of its divisors is an integer number (1737466920).

Almost surely, 2^25791721816 is an apocalyptic number.

It is an amenable number.

25791721816 is an abundant number, since it is smaller than the sum of its proper divisors (29807219624).

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

25791721816 is a wasteful number, since it uses less digits than its factorization.

25791721816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2758063 (or 2758059 counting only the distinct ones).

The product of its digits is 423360, while the sum is 49.

The spelling of 25791721816 in words is "twenty-five billion, seven hundred ninety-one million, seven hundred twenty-one thousand, eight hundred sixteen".