816123520 has 32 divisors (see below), whose sum is σ = 1951046820. Its totient is φ = 326449152.

The previous prime is 816123509. The next prime is 816123533. The reversal of 816123520 is 25321618.

It can be written as a sum of positive squares in 2 ways, for example, as 756030016 + 60093504 = 27496^2 + 7752^2 .

It is a tau number, because it is divible by the number of its divisors (32).

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, 636957 + ... + 638236.

Almost surely, 2^816123520 is an apocalyptic number.

816123520 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

816123520 is an abundant number, since it is smaller than the sum of its proper divisors (1134923300).

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

816123520 is a wasteful number, since it uses less digits than its factorization.

816123520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1275212 (or 1275200 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 816123520 is about 28567.8756648092. The cubic root of 816123520 is about 934.5128941128.

The spelling of 816123520 in words is "eight hundred sixteen million, one hundred twenty-three thousand, five hundred twenty".