81576971 has 16 divisors (see below), whose sum is σ = 99061440. Its totient is φ = 65681280.

The previous prime is 81576967. The next prime is 81576991. The reversal of 81576971 is 17967518.

It is not a de Polignac number, because 81576971 - 2² = 81576967 is a prime.

It is a Smith number, since the sum of its digits (44) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81576991) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2081 + ... + 12941.

It is an arithmetic number, because the mean of its divisors is an integer number (6191340).

Almost surely, 2^81576971 is an apocalyptic number.

81576971 is a deficient number, since it is larger than the sum of its proper divisors (17484469).

81576971 is a wasteful number, since it uses less digits than its factorization.

81576971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10934.

The product of its digits is 105840, while the sum is 44.

The square root of 81576971 is about 9031.9970659871. The cubic root of 81576971 is about 433.6997700584.

The spelling of 81576971 in words is "eighty-one million, five hundred seventy-six thousand, nine hundred seventy-one".