25515806680 has 128 divisors (see below), whose sum is σ = 70826716800. Its totient is φ = 8056184832.

The previous prime is 25515806653. The next prime is 25515806683. The reversal of 25515806680 is 8660851552.

It is a happy number.

It is a super-2 number, since 2×25515806680² (a number of 22 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 25515806680.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25515806683) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1568026 + ... + 1584214.

It is an arithmetic number, because the mean of its divisors is an integer number (553333725).

Almost surely, 2^25515806680 is an apocalyptic number.

25515806680 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 25515806680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35413358400).

25515806680 is an abundant number, since it is smaller than the sum of its proper divisors (45310910120).

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

25515806680 is a wasteful number, since it uses less digits than its factorization.

25515806680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16653 (or 16649 counting only the distinct ones).

The product of its (nonzero) digits is 576000, while the sum is 46.

The spelling of 25515806680 in words is "twenty-five billion, five hundred fifteen million, eight hundred six thousand, six hundred eighty".