81697732 has 12 divisors (see below), whose sum is σ = 143236240. Its totient is φ = 40773096.

The previous prime is 81697709. The next prime is 81697747. The reversal of 81697732 is 23779618.

It is a happy number.

It is a hoax number, since the sum of its digits (43) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16482 + ... + 20857.

Almost surely, 2^81697732 is an apocalyptic number.

It is an amenable number.

81697732 is a deficient number, since it is larger than the sum of its proper divisors (61538508).

81697732 is a wasteful number, since it uses less digits than its factorization.

81697732 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37890 (or 37888 counting only the distinct ones).

The product of its digits is 127008, while the sum is 43.

The square root of 81697732 is about 9038.6797708515. The cubic root of 81697732 is about 433.9136710931.

The spelling of 81697732 in words is "eighty-one million, six hundred ninety-seven thousand, seven hundred thirty-two".