819121680 has 320 divisors, whose sum is σ = 3139799040. Its totient is φ = 194918400.

The previous prime is 819121669. The next prime is 819121729. The reversal of 819121680 is 86121918.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 870010 + ... + 870950.

It is an arithmetic number, because the mean of its divisors is an integer number (9811872).

Almost surely, 2^819121680 is an apocalyptic number.

819121680 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 819121680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1569899520).

819121680 is an abundant number, since it is smaller than the sum of its proper divisors (2320677360).

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

819121680 is a wasteful number, since it uses less digits than its factorization.

819121680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1007 (or 995 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 36.

The square root of 819121680 is about 28620.3018852003. The cubic root of 819121680 is about 935.6558563886.

The spelling of 819121680 in words is "eight hundred nineteen million, one hundred twenty-one thousand, six hundred eighty".