81318532 has 12 divisors (see below), whose sum is σ = 142522380. Its totient is φ = 40597856.

The previous prime is 81318527. The next prime is 81318533. The reversal of 81318532 is 23581318.

It can be written as a sum of positive squares in 2 ways, for example, as 80568576 + 749956 = 8976^2 + 866^2 .

It is a super-2 number, since 2×81318532² = 13225407293270048, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81318494 and 81318503.

It is not an unprimeable number, because it can be changed into a prime (81318533) 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 3 ways as a sum of consecutive naturals, for example, 12307 + ... + 17722.

It is an arithmetic number, because the mean of its divisors is an integer number (11876865).

Almost surely, 2^81318532 is an apocalyptic number.

It is an amenable number.

81318532 is a deficient number, since it is larger than the sum of its proper divisors (61203848).

81318532 is a wasteful number, since it uses less digits than its factorization.

81318532 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30710 (or 30708 counting only the distinct ones).

The product of its digits is 5760, while the sum is 31.

The square root of 81318532 is about 9017.6788587751. The cubic root of 81318532 is about 433.2412930095.

The spelling of 81318532 in words is "eighty-one million, three hundred eighteen thousand, five hundred thirty-two".