81731768 has 16 divisors (see below), whose sum is σ = 161313000. Its totient is φ = 38714976.

The previous prime is 81731743. The next prime is 81731789. The reversal of 81731768 is 86713718.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 268703 + ... + 269006.

Almost surely, 2^81731768 is an apocalyptic number.

It is an amenable number.

81731768 is a deficient number, since it is larger than the sum of its proper divisors (79581232).

81731768 is a wasteful number, since it uses less digits than its factorization.

81731768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 537734 (or 537730 counting only the distinct ones).

The product of its digits is 56448, while the sum is 41.

The square root of 81731768 is about 9040.5623718882. The cubic root of 81731768 is about 433.9739201555.

The spelling of 81731768 in words is "eighty-one million, seven hundred thirty-one thousand, seven hundred sixty-eight".