81724932971 has 4 divisors (see below), whose sum is σ = 89154472344. Its totient is φ = 74295393600.

The previous prime is 81724932941. The next prime is 81724932977. The reversal of 81724932971 is 17923942718.

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

It is a cyclic number.

It is not a de Polignac number, because 81724932971 - 2⁶ = 81724932907 is a prime.

It is a super-2 number, since 2×81724932971² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81724932977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3714769670 + ... + 3714769691.

It is an arithmetic number, because the mean of its divisors is an integer number (22288618086).

Almost surely, 2^81724932971 is an apocalyptic number.

81724932971 is a deficient number, since it is larger than the sum of its proper divisors (7429539373).

81724932971 is a wasteful number, since it uses less digits than its factorization.

81724932971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7429539372.

The product of its digits is 1524096, while the sum is 53.

The spelling of 81724932971 in words is "eighty-one billion, seven hundred twenty-four million, nine hundred thirty-two thousand, nine hundred seventy-one".