81290313 has 12 divisors (see below), whose sum is σ = 126451780. Its totient is φ = 50024736.

The previous prime is 81290309. The next prime is 81290323. The reversal of 81290313 is 31309218.

It can be written as a sum of positive squares in 2 ways, for example, as 53538489 + 27751824 = 7317^2 + 5268^2 .

It is not a de Polignac number, because 81290313 - 2² = 81290309 is a prime.

It is a super-2 number, since 2×81290313² = 13216229975275938, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81290323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 347278 + ... + 347511.

Almost surely, 2^81290313 is an apocalyptic number.

It is an amenable number.

81290313 is a deficient number, since it is larger than the sum of its proper divisors (45161467).

81290313 is a wasteful number, since it uses less digits than its factorization.

81290313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 694808 (or 694805 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 81290313 is about 9016.1140742562. The cubic root of 81290313 is about 433.1911730258.

It can be divided in two parts, 812 and 90313, that added together give a cube (91125 = 45³).

The spelling of 81290313 in words is "eighty-one million, two hundred ninety thousand, three hundred thirteen".