81996744851 has 8 divisors (see below), whose sum is σ = 93971600640. Its totient is φ = 70087147848.

The previous prime is 81996744833. The next prime is 81996744919. The reversal of 81996744851 is 15844769918.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81996744851 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81996744551) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16312001 + ... + 16317026.

It is an arithmetic number, because the mean of its divisors is an integer number (11746450080).

Almost surely, 2^81996744851 is an apocalyptic number.

81996744851 is a deficient number, since it is larger than the sum of its proper divisors (11974855789).

81996744851 is a wasteful number, since it uses less digits than its factorization.

81996744851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32629393.

The product of its digits is 17418240, while the sum is 62.

The spelling of 81996744851 in words is "eighty-one billion, nine hundred ninety-six million, seven hundred forty-four thousand, eight hundred fifty-one".