816891935872 has 64 divisors (see below), whose sum is σ = 1732060459800. Its totient is φ = 382427725824.

The previous prime is 816891935863. The next prime is 816891935887. The reversal of 816891935872 is 278539198618.

It can be written as a sum of positive squares in 4 ways, for example, as 648772255296 + 168119680576 = 805464^2 + 410024^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is a junction number, because it is equal to n+sod(n) for n = 816891935798 and 816891935807.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 552597 + ... + 1392532.

Almost surely, 2^816891935872 is an apocalyptic number.

It is an amenable number.

816891935872 is an abundant number, since it is smaller than the sum of its proper divisors (915168523928).

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

816891935872 is a wasteful number, since it uses less digits than its factorization.

816891935872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1945353 (or 1945341 counting only the distinct ones).

The product of its digits is 52254720, while the sum is 67.

The spelling of 816891935872 in words is "eight hundred sixteen billion, eight hundred ninety-one million, nine hundred thirty-five thousand, eight hundred seventy-two".