81885825 has 36 divisors (see below), whose sum is σ = 167622208. Its totient is φ = 37432800.

The previous prime is 81885799. The next prime is 81885841. The reversal of 81885825 is 52858818.

It is not a de Polignac number, because 81885825 - 2⁶ = 81885761 is a prime.

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

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 24421 + ... + 27570.

Almost surely, 2^81885825 is an apocalyptic number.

It is an amenable number.

81885825 is an abundant number, since it is smaller than the sum of its proper divisors (85736383).

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

81885825 is a wasteful number, since it uses less digits than its factorization.

81885825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52014 (or 52006 counting only the distinct ones).

The product of its digits is 204800, while the sum is 45.

The square root of 81885825 is about 9049.0786823853. The cubic root of 81885825 is about 434.2464162302.

The spelling of 81885825 in words is "eighty-one million, eight hundred eighty-five thousand, eight hundred twenty-five".