81133625 has 8 divisors (see below), whose sum is σ = 101254920. Its totient is φ = 64906800.

The previous prime is 81133601. The next prime is 81133631. The reversal of 81133625 is 52633118.

It can be written as a sum of positive squares in 4 ways, for example, as 1138489 + 79995136 = 1067^2 + 8944^2 .

It is not a de Polignac number, because 81133625 - 2¹⁶ = 81068089 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, 324410 + ... + 324659.

It is an arithmetic number, because the mean of its divisors is an integer number (12656865).

Almost surely, 2^81133625 is an apocalyptic number.

It is an amenable number.

81133625 is a deficient number, since it is larger than the sum of its proper divisors (20121295).

81133625 is an equidigital number, since it uses as much as digits as its factorization.

81133625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 649084 (or 649074 counting only the distinct ones).

The product of its digits is 4320, while the sum is 29.

The square root of 81133625 is about 9007.4205519671. The cubic root of 81133625 is about 432.9126670420.

The spelling of 81133625 in words is "eighty-one million, one hundred thirty-three thousand, six hundred twenty-five".