81917732 has 12 divisors (see below), whose sum is σ = 154383516. Its totient is φ = 37808160.

The previous prime is 81917729. The next prime is 81917791. The reversal of 81917732 is 23771918.

It can be written as a sum of positive squares in 2 ways, for example, as 10278436 + 71639296 = 3206^2 + 8464^2 .

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, 787619 + ... + 787722.

It is an arithmetic number, because the mean of its divisors is an integer number (12865293).

Almost surely, 2^81917732 is an apocalyptic number.

It is an amenable number.

81917732 is a deficient number, since it is larger than the sum of its proper divisors (72465784).

81917732 is a wasteful number, since it uses less digits than its factorization.

81917732 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1575358 (or 1575356 counting only the distinct ones).

The product of its digits is 21168, while the sum is 38.

The square root of 81917732 is about 9050.8415078378. The cubic root of 81917732 is about 434.3028106109.

The spelling of 81917732 in words is "eighty-one million, nine hundred seventeen thousand, seven hundred thirty-two".