81996723 has 12 divisors (see below), whose sum is σ = 124673640. Its totient is φ = 51787296.

The previous prime is 81996721. The next prime is 81996727. The reversal of 81996723 is 32769918.

It is not a de Polignac number, because 81996723 - 2¹ = 81996721 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (81996721) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 239586 + ... + 239927.

It is an arithmetic number, because the mean of its divisors is an integer number (10389470).

Almost surely, 2^81996723 is an apocalyptic number.

81996723 is a deficient number, since it is larger than the sum of its proper divisors (42676917).

81996723 is a wasteful number, since it uses less digits than its factorization.

81996723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 479538 (or 479535 counting only the distinct ones).

The product of its digits is 163296, while the sum is 45.

The square root of 81996723 is about 9055.2041942741. The cubic root of 81996723 is about 434.4423611559.

The spelling of 81996723 in words is "eighty-one million, nine hundred ninety-six thousand, seven hundred twenty-three".