81313137 has 12 divisors (see below), whose sum is σ = 117643344. Its totient is φ = 54120600.

The previous prime is 81313117. The next prime is 81313139. The reversal of 81313137 is 73131318.

It is not a de Polignac number, because 81313137 - 2¹⁸ = 81050993 is a prime.

It is a super-2 number, since 2×81313137² = 13223652497561538, which contains 22 as substring.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 81313137.

It is not an unprimeable number, because it can be changed into a prime (81313139) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1239 + ... + 12812.

It is an arithmetic number, because the mean of its divisors is an integer number (9803612).

Almost surely, 2^81313137 is an apocalyptic number.

It is an amenable number.

81313137 is a deficient number, since it is larger than the sum of its proper divisors (36330207).

81313137 is a wasteful number, since it uses less digits than its factorization.

81313137 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14700 (or 14697 counting only the distinct ones).

The product of its digits is 1512, while the sum is 27.

The square root of 81313137 is about 9017.3797191867. The cubic root of 81313137 is about 433.2317118049.

The spelling of 81313137 in words is "eighty-one million, three hundred thirteen thousand, one hundred thirty-seven".