811979913888 has 768 divisors, whose sum is σ = 2901878784000. Its totient is φ = 217520640000.

The previous prime is 811979913853. The next prime is 811979913911. The reversal of 811979913888 is 888319979118.

811979913888 is a `hidden beast` number, since 81 + 19 + 79 + 91 + 388 + 8 = 666.

It is a super-2 number, since 2×811979913888² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (72).

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 127 ways as a sum of consecutive naturals, for example, 386840263 + ... + 386842361.

It is an arithmetic number, because the mean of its divisors is an integer number (3778488000).

Almost surely, 2^811979913888 is an apocalyptic number.

811979913888 is a gapful number since it is divisible by the number (88) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 811979913888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1450939392000).

811979913888 is an abundant number, since it is smaller than the sum of its proper divisors (2089898870112).

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

811979913888 is a wasteful number, since it uses less digits than its factorization.

811979913888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2274 (or 2260 counting only the distinct ones).

The product of its digits is 62705664, while the sum is 72.

The spelling of 811979913888 in words is "eight hundred eleven billion, nine hundred seventy-nine million, nine hundred thirteen thousand, eight hundred eighty-eight".