81657712 has 10 divisors (see below), whose sum is σ = 158211848. Its totient is φ = 40828848.

The previous prime is 81657701. The next prime is 81657733. The reversal of 81657712 is 21775618.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2551788 + ... + 2551819.

Almost surely, 2^81657712 is an apocalyptic number.

It is an amenable number.

81657712 is a deficient number, since it is larger than the sum of its proper divisors (76554136).

81657712 is a wasteful number, since it uses less digits than its factorization.

81657712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5103615 (or 5103609 counting only the distinct ones).

The product of its digits is 23520, while the sum is 37.

The square root of 81657712 is about 9036.4656807847. The cubic root of 81657712 is about 433.8428080025.

It can be divided in two parts, 81657 and 712, that added together give a square (82369 = 287²).

The spelling of 81657712 in words is "eighty-one million, six hundred fifty-seven thousand, seven hundred twelve".