25565056440 has 512 divisors, whose sum is σ = 99532800000. Its totient is φ = 5097830400.

The previous prime is 25565056421. The next prime is 25565056441. The reversal of 25565056440 is 4465056552.

It is a happy number.

It is a super-2 number, since 2×25565056440² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 25565056392 and 25565056401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25565056441) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 42679261 + ... + 42679859.

It is an arithmetic number, because the mean of its divisors is an integer number (194400000).

Almost surely, 2^25565056440 is an apocalyptic number.

25565056440 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 25565056440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49766400000).

25565056440 is an abundant number, since it is smaller than the sum of its proper divisors (73967743560).

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

25565056440 is a wasteful number, since it uses less digits than its factorization.

25565056440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 811 (or 807 counting only the distinct ones).

The product of its (nonzero) digits is 720000, while the sum is 42.

The spelling of 25565056440 in words is "twenty-five billion, five hundred sixty-five million, fifty-six thousand, four hundred forty".