81309337812120 has 256 divisors, whose sum is σ = 272363247636480. Its totient is φ = 19247894668800.

The previous prime is 81309337812013. The next prime is 81309337812127. The reversal of 81309337812120 is 2121873390318.

It is a super-2 number, since 2×81309337812120² (a number of 29 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81309337812120.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81309337812127) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 218169535 + ... + 218541905.

It is an arithmetic number, because the mean of its divisors is an integer number (1063918936080).

Almost surely, 2^{81309337812120} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81309337812120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (136181623818240).

81309337812120 is an abundant number, since it is smaller than the sum of its proper divisors (191053909824360).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81309337812120 is a wasteful number, since it uses less digits than its factorization.

81309337812120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 376286 (or 376282 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 48.

The spelling of 81309337812120 in words is "eighty-one trillion, three hundred nine billion, three hundred thirty-seven million, eight hundred twelve thousand, one hundred twenty".