81973571 has 4 divisors (see below), whose sum is σ = 82402944. Its totient is φ = 81544200.

The previous prime is 81973561. The next prime is 81973603. The reversal of 81973571 is 17537918.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81973571 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81973501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 214400 + ... + 214781.

It is an arithmetic number, because the mean of its divisors is an integer number (20600736).

Almost surely, 2^81973571 is an apocalyptic number.

81973571 is a deficient number, since it is larger than the sum of its proper divisors (429373).

81973571 is a wasteful number, since it uses less digits than its factorization.

81973571 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 429372.

The product of its digits is 52920, while the sum is 41.

The square root of 81973571 is about 9053.9257231325. The cubic root of 81973571 is about 434.4014686423.

The spelling of 81973571 in words is "eighty-one million, nine hundred seventy-three thousand, five hundred seventy-one".