81731715 has 64 divisors (see below), whose sum is σ = 148176000. Its totient is φ = 38191104.

The previous prime is 81731701. The next prime is 81731743. The reversal of 81731715 is 51713718.

81731715 is an esthetic number in base 12, because in such base its adjacent digits differ by 1.

It is not a de Polignac number, because 81731715 - 2⁶ = 81731651 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 548461 + ... + 548609.

It is an arithmetic number, because the mean of its divisors is an integer number (2315250).

Almost surely, 2^81731715 is an apocalyptic number.

81731715 is a deficient number, since it is larger than the sum of its proper divisors (66444285).

81731715 is a wasteful number, since it uses less digits than its factorization.

81731715 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 296.

The product of its digits is 5880, while the sum is 33.

The square root of 81731715 is about 9040.5594406541. The cubic root of 81731715 is about 433.9738263502.

The spelling of 81731715 in words is "eighty-one million, seven hundred thirty-one thousand, seven hundred fifteen".