81992023064 has 32 divisors (see below), whose sum is σ = 183336203520. Its totient is φ = 33611636256.

The previous prime is 81992023007. The next prime is 81992023073. The reversal of 81992023064 is 46032029918.

It is a super-2 number, since 2×81992023064² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31827914 + ... + 31830489.

It is an arithmetic number, because the mean of its divisors is an integer number (5729256360).

Almost surely, 2^81992023064 is an apocalyptic number.

It is an amenable number.

81992023064 is an abundant number, since it is smaller than the sum of its proper divisors (101344180456).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81992023064 is a wasteful number, since it uses less digits than its factorization.

81992023064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63658439 (or 63658435 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 44.

The spelling of 81992023064 in words is "eighty-one billion, nine hundred ninety-two million, twenty-three thousand, sixty-four".