81609392 has 10 divisors (see below), whose sum is σ = 158118228. Its totient is φ = 40804688.

The previous prime is 81609379. The next prime is 81609397. The reversal of 81609392 is 29390618.

It is not an unprimeable number, because it can be changed into a prime (81609397) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2550278 + ... + 2550309.

Almost surely, 2^81609392 is an apocalyptic number.

It is an amenable number.

81609392 is a deficient number, since it is larger than the sum of its proper divisors (76508836).

81609392 is a wasteful number, since it uses less digits than its factorization.

81609392 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5100595 (or 5100589 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 81609392 is about 9033.7916734890. The cubic root of 81609392 is about 433.7572173083.

The spelling of 81609392 in words is "eighty-one million, six hundred nine thousand, three hundred ninety-two".