81868425 has 24 divisors (see below), whose sum is σ = 136271040. Its totient is φ = 43368000.

The previous prime is 81868399. The next prime is 81868433. The reversal of 81868425 is 52486818.

It is not a de Polignac number, because 81868425 - 2⁵ = 81868393 is a prime.

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, 7711 + ... + 14939.

It is an arithmetic number, because the mean of its divisors is an integer number (5677960).

Almost surely, 2^81868425 is an apocalyptic number.

It is an amenable number.

81868425 is a deficient number, since it is larger than the sum of its proper divisors (54402615).

81868425 is a wasteful number, since it uses less digits than its factorization.

81868425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7393 (or 7388 counting only the distinct ones).

The product of its digits is 122880, while the sum is 42.

The square root of 81868425 is about 9048.1172074637. The cubic root of 81868425 is about 434.2156562344.

The spelling of 81868425 in words is "eighty-one million, eight hundred sixty-eight thousand, four hundred twenty-five".