25634398440 has 256 divisors, whose sum is σ = 89791395840. Its totient is φ = 5733504000.

The previous prime is 25634398393. The next prime is 25634398441. The reversal of 25634398440 is 4489343652.

It is a self number, because there is not a number n which added to its sum of digits gives 25634398440.

It is not an unprimeable number, because it can be changed into a prime (25634398441) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 10810455 + ... + 10812825.

It is an arithmetic number, because the mean of its divisors is an integer number (350747640).

Almost surely, 2^25634398440 is an apocalyptic number.

25634398440 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 25634398440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44895697920).

25634398440 is an abundant number, since it is smaller than the sum of its proper divisors (64156997400).

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

25634398440 is a wasteful number, since it uses less digits than its factorization.

25634398440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2664 (or 2660 counting only the distinct ones).

The product of its (nonzero) digits is 2488320, while the sum is 48.

The spelling of 25634398440 in words is "twenty-five billion, six hundred thirty-four million, three hundred ninety-eight thousand, four hundred forty".