815923921920 has 176 divisors, whose sum is σ = 2614936056000. Its totient is φ = 217141641216.

The previous prime is 815923921867. The next prime is 815923921931. The reversal of 815923921920 is 29129329518.

It is a super-2 number, since 2×815923921920² (a number of 25 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (51) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7611414 + ... + 7717866.

Almost surely, 2^815923921920 is an apocalyptic number.

815923921920 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 815923921920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1307468028000).

815923921920 is an abundant number, since it is smaller than the sum of its proper divisors (1799012134080).

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

815923921920 is a wasteful number, since it uses less digits than its factorization.

815923921920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106980 (or 106962 counting only the distinct ones).

The product of its (nonzero) digits is 699840, while the sum is 51.

The spelling of 815923921920 in words is "eight hundred fifteen billion, nine hundred twenty-three million, nine hundred twenty-one thousand, nine hundred twenty".