81092989856 has 24 divisors (see below), whose sum is σ = 161116526340. Its totient is φ = 40174507008.

The previous prime is 81092989849. The next prime is 81092989903. The reversal of 81092989856 is 65898929018.

It can be written as a sum of positive squares in 2 ways, for example, as 79467610000 + 1625379856 = 281900^2 + 40316^2 .

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 81092989792 and 81092989801.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11621081 + ... + 11628056.

Almost surely, 2^81092989856 is an apocalyptic number.

It is an amenable number.

81092989856 is a deficient number, since it is larger than the sum of its proper divisors (80023536484).

81092989856 is a wasteful number, since it uses less digits than its factorization.

81092989856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23249256 (or 23249248 counting only the distinct ones).

The product of its (nonzero) digits is 22394880, while the sum is 65.

The spelling of 81092989856 in words is "eighty-one billion, ninety-two million, nine hundred eighty-nine thousand, eight hundred fifty-six".