81358625 has 8 divisors (see below), whose sum is σ = 101535720. Its totient is φ = 65086800.

The previous prime is 81358609. The next prime is 81358633. The reversal of 81358625 is 52685318.

It can be written as a sum of positive squares in 4 ways, for example, as 1934881 + 79423744 = 1391^2 + 8912^2 .

It is not a de Polignac number, because 81358625 - 2⁴ = 81358609 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 325310 + ... + 325559.

It is an arithmetic number, because the mean of its divisors is an integer number (12691965).

Almost surely, 2^81358625 is an apocalyptic number.

It is an amenable number.

81358625 is a deficient number, since it is larger than the sum of its proper divisors (20177095).

81358625 is an equidigital number, since it uses as much as digits as its factorization.

81358625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 650884 (or 650874 counting only the distinct ones).

The product of its digits is 57600, while the sum is 38.

The square root of 81358625 is about 9019.9016070022. The cubic root of 81358625 is about 433.3124825602.

The spelling of 81358625 in words is "eighty-one million, three hundred fifty-eight thousand, six hundred twenty-five".