25538321816 has 32 divisors (see below), whose sum is σ = 55256298240. Its totient is φ = 10838730528.

The previous prime is 25538321813. The next prime is 25538321843. The reversal of 25538321816 is 61812383552.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25538321813) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2208026 + ... + 2219561.

It is an arithmetic number, because the mean of its divisors is an integer number (1726759320).

Almost surely, 2^25538321816 is an apocalyptic number.

It is an amenable number.

25538321816 is an abundant number, since it is smaller than the sum of its proper divisors (29717976424).

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

25538321816 is a wasteful number, since it uses less digits than its factorization.

25538321816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4427703 (or 4427699 counting only the distinct ones).

The product of its digits is 345600, while the sum is 44.

The spelling of 25538321816 in words is "twenty-five billion, five hundred thirty-eight million, three hundred twenty-one thousand, eight hundred sixteen".