816643120 has 20 divisors (see below), whose sum is σ = 1898695440. Its totient is φ = 326657216.

The previous prime is 816643117. The next prime is 816643159. The reversal of 816643120 is 21346618.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (20).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5103940 + ... + 5104099.

It is an arithmetic number, because the mean of its divisors is an integer number (94934772).

Almost surely, 2^816643120 is an apocalyptic number.

816643120 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

816643120 is an abundant number, since it is smaller than the sum of its proper divisors (1082052320).

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

816643120 is a wasteful number, since it uses less digits than its factorization.

816643120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10208052 (or 10208046 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 816643120 is about 28576.9683486545. The cubic root of 816643120 is about 934.7111769604.

Adding to 816643120 its reverse (21346618), we get a palindrome (837989738).

The spelling of 816643120 in words is "eight hundred sixteen million, six hundred forty-three thousand, one hundred twenty".