81179515922 has 54 divisors (see below), whose sum is σ = 129060405621. Its totient is φ = 38295227520.

The previous prime is 81179515867. The next prime is 81179515939. The reversal of 81179515922 is 22951597118.

It can be written as a sum of positive squares in 2 ways, for example, as 80968133401 + 211382521 = 284549^2 + 14539^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=201469.

It is a super-2 number, since 2×81179515922² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 836902178 + ... + 836902274.

Almost surely, 2^81179515922 is an apocalyptic number.

81179515922 is a deficient number, since it is larger than the sum of its proper divisors (47880889699).

81179515922 is an frugal number, since it uses more digits than its factorization.

81179515922 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 392 (or 197 counting only the distinct ones).

The product of its digits is 453600, while the sum is 50.

Multiplying 81179515922 by its sum of digits (50), we get a square (4058975796100 = 2014690²).

The spelling of 81179515922 in words is "eighty-one billion, one hundred seventy-nine million, five hundred fifteen thousand, nine hundred twenty-two".