25991888400 has 135 divisors (see below), whose sum is σ = 90232653901. Its totient is φ = 6928590720.

The previous prime is 25991888389. The next prime is 25991888437. The reversal of 25991888400 is 488819952.

The square root of 25991888400 is 161220.

It is a perfect power (a square), and thus also a powerful number.

25991888400 is a `hidden beast` number, since 2 + 59 + 9 + 188 + 8 + 400 = 666.

It can be written as a sum of positive squares in only one way, i.e., 9357079824 + 16634808576 = 96732^2 + 128976^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 9671857 + ... + 9674543.

Almost surely, 2^25991888400 is an apocalyptic number.

25991888400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

25991888400 is the 161220-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 25991888400

25991888400 is an abundant number, since it is smaller than the sum of its proper divisors (64240765501).

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

25991888400 is an equidigital number, since it uses as much as digits as its factorization.

25991888400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5398 (or 2697 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 54.

The spelling of 25991888400 in words is "twenty-five billion, nine hundred ninety-one million, eight hundred eighty-eight thousand, four hundred".