813128899566816 has 288 divisors, whose sum is σ = 2644003412563968. Its totient is φ = 232205259340800.

The previous prime is 813128899566811. The next prime is 813128899566913. The reversal of 813128899566816 is 618665998821318.

813128899566816 is a `hidden beast` number, since 8 + 1 + 31 + 2 + 8 + 8 + 9 + 9 + 566 + 8 + 16 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a super-2 number, since 2×813128899566816² (a number of 31 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (813128899566811) 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, 38696458326 + ... + 38696479338.

It is an arithmetic number, because the mean of its divisors is an integer number (9180567404736).

Almost surely, 2^{813128899566816} 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 813128899566816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1322001706281984).

813128899566816 is an abundant number, since it is smaller than the sum of its proper divisors (1830874512997152).

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

813128899566816 is a wasteful number, since it uses less digits than its factorization.

813128899566816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29814 (or 29803 counting only the distinct ones).

The product of its digits is 2149908480, while the sum is 81.

The spelling of 813128899566816 in words is "eight hundred thirteen trillion, one hundred twenty-eight billion, eight hundred ninety-nine million, five hundred sixty-six thousand, eight hundred sixteen".