81653925 has 24 divisors (see below), whose sum is σ = 142108960. Its totient is φ = 41256000.

The previous prime is 81653917. The next prime is 81653951. The reversal of 81653925 is 52935618.

It is not a de Polignac number, because 81653925 - 2³ = 81653917 is a prime.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 27226 + ... + 30075.

Almost surely, 2^81653925 is an apocalyptic number.

It is an amenable number.

81653925 is a deficient number, since it is larger than the sum of its proper divisors (60455035).

81653925 is a wasteful number, since it uses less digits than its factorization.

81653925 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57333 (or 57328 counting only the distinct ones).

The product of its digits is 64800, while the sum is 39.

The square root of 81653925 is about 9036.2561384680. The cubic root of 81653925 is about 433.8361011932.

It can be divided in two parts, 8165 and 3925, that added together give a triangular number (12090 = T₁₅₅).

The spelling of 81653925 in words is "eighty-one million, six hundred fifty-three thousand, nine hundred twenty-five".