25197434640 has 300 divisors, whose sum is σ = 101803775436. Its totient is φ = 5759341056.

The previous prime is 25197434557. The next prime is 25197434659. The reversal of 25197434640 is 4643479152.

25197434640 is a `hidden beast` number, since 2 + 519 + 74 + 3 + 4 + 64 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 10989748224 + 14207686416 = 104832^2 + 119196^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 277842 + ... + 357198.

Almost surely, 2^25197434640 is an apocalyptic number.

25197434640 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 25197434640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50901887718).

25197434640 is an abundant number, since it is smaller than the sum of its proper divisors (76606340796).

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

25197434640 is a wasteful number, since it uses less digits than its factorization.

25197434640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79396 (or 79374 counting only the distinct ones).

The product of its (nonzero) digits is 725760, while the sum is 45.

The spelling of 25197434640 in words is "twenty-five billion, one hundred ninety-seven million, four hundred thirty-four thousand, six hundred forty".