81892664139 has 48 divisors (see below), whose sum is σ = 131841077760. Its totient is φ = 44575539840.

The previous prime is 81892664137. The next prime is 81892664179. The reversal of 81892664139 is 93146629818.

It is not a de Polignac number, because 81892664139 - 2¹ = 81892664137 is a prime.

It is a super-2 number, since 2×81892664139² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81892664137) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 517582 + ... + 657020.

It is an arithmetic number, because the mean of its divisors is an integer number (2746689120).

Almost surely, 2^81892664139 is an apocalyptic number.

81892664139 is a deficient number, since it is larger than the sum of its proper divisors (49948413621).

81892664139 is a wasteful number, since it uses less digits than its factorization.

81892664139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139540 (or 139503 counting only the distinct ones).

The product of its digits is 4478976, while the sum is 57.

It can be divided in two parts, 81892 and 664139, that added together give a triangular number (746031 = T₁₂₂₁).

The spelling of 81892664139 in words is "eighty-one billion, eight hundred ninety-two million, six hundred sixty-four thousand, one hundred thirty-nine".