816817920 has 144 divisors (see below), whose sum is σ = 2679684000. Its totient is φ = 211894272.

The previous prime is 816817909. The next prime is 816817993. The reversal of 816817920 is 29718618.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 139206 + ... + 144954.

Almost surely, 2^816817920 is an apocalyptic number.

816817920 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 816817920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1339842000).

816817920 is an abundant number, since it is smaller than the sum of its proper divisors (1862866080).

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

816817920 is a wasteful number, since it uses less digits than its factorization.

816817920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5810 (or 5796 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 42.

The square root of 816817920 is about 28580.0265920100. The cubic root of 816817920 is about 934.7778629066. Note that the first 3 decimals are identical.

The spelling of 816817920 in words is "eight hundred sixteen million, eight hundred seventeen thousand, nine hundred twenty".