816111321505920 has 4096 divisors, whose sum is σ = 3540249815040000. Its totient is φ = 175352905728000.

The previous prime is 816111321505891. The next prime is 816111321505937. The reversal of 816111321505920 is 29505123111618.

816111321505920 is a `hidden beast` number, since 8 + 1 + 6 + 1 + 1 + 1 + 3 + 2 + 1 + 50 + 592 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 511 ways as a sum of consecutive naturals, for example, 746670924894 + ... + 746670925986.

It is an arithmetic number, because the mean of its divisors is an integer number (864318802500).

Almost surely, 2^{816111321505920} is an apocalyptic number.

816111321505920 is a gapful number since it is divisible by the number (80) 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 816111321505920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1770124907520000).

816111321505920 is an abundant number, since it is smaller than the sum of its proper divisors (2724138493534080).

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

816111321505920 is a wasteful number, since it uses less digits than its factorization.

816111321505920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1364 (or 1346 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 45.

The spelling of 816111321505920 in words is "eight hundred sixteen trillion, one hundred eleven billion, three hundred twenty-one million, five hundred five thousand, nine hundred twenty".