81318957 has 8 divisors (see below), whose sum is σ = 108912384. Its totient is φ = 53969088.

The previous prime is 81318947. The next prime is 81318959. The reversal of 81318957 is 75981318.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81318957 - 2⁶ = 81318893 is a prime.

It is a super-2 number, since 2×81318957² = 13225545535135698, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81318959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 60108 + ... + 61445.

It is an arithmetic number, because the mean of its divisors is an integer number (13614048).

Almost surely, 2^81318957 is an apocalyptic number.

It is an amenable number.

81318957 is a deficient number, since it is larger than the sum of its proper divisors (27593427).

81318957 is a wasteful number, since it uses less digits than its factorization.

81318957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121779.

The product of its digits is 60480, while the sum is 42.

The square root of 81318957 is about 9017.7024235667. The cubic root of 81318957 is about 433.2420477666.

The spelling of 81318957 in words is "eighty-one million, three hundred eighteen thousand, nine hundred fifty-seven".