811915105840 has 80 divisors (see below), whose sum is σ = 1897206696000. Its totient is φ = 323133981696.

The previous prime is 811915105811. The next prime is 811915105919. The reversal of 811915105840 is 48501519118.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×811915105840² (a number of 25 digits) contains 22 as substring.

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 15 ways as a sum of consecutive naturals, for example, 17418886 + ... + 17465434.

It is an arithmetic number, because the mean of its divisors is an integer number (23715083700).

Almost surely, 2^811915105840 is an apocalyptic number.

811915105840 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

811915105840 is an abundant number, since it is smaller than the sum of its proper divisors (1085291590160).

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

811915105840 is a wasteful number, since it uses less digits than its factorization.

811915105840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47654 (or 47648 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 43.

The spelling of 811915105840 in words is "eight hundred eleven billion, nine hundred fifteen million, one hundred five thousand, eight hundred forty".