25164538581 has 32 divisors (see below), whose sum is σ = 43469117440. Its totient is φ = 12574989504.

The previous prime is 25164538549. The next prime is 25164538589. The reversal of 25164538581 is 18583546152.

It is not a de Polignac number, because 25164538581 - 2⁵ = 25164538549 is a prime.

It is a super-2 number, since 2×25164538581² (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 25164538581.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25164538589) 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, 2420545 + ... + 2430918.

It is an arithmetic number, because the mean of its divisors is an integer number (1358409920).

Almost surely, 2^25164538581 is an apocalyptic number.

25164538581 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

25164538581 is a deficient number, since it is larger than the sum of its proper divisors (18304578859).

25164538581 is a wasteful number, since it uses less digits than its factorization.

25164538581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4851505.

The product of its digits is 1152000, while the sum is 48.

The spelling of 25164538581 in words is "twenty-five billion, one hundred sixty-four million, five hundred thirty-eight thousand, five hundred eighty-one".