816589920 has 144 divisors (see below), whose sum is σ = 2630175408. Its totient is φ = 212904960.

The previous prime is 816589853. The next prime is 816589927. The reversal of 816589920 is 29985618.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 816589920.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (816589927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4889677 + ... + 4889843.

It is an arithmetic number, because the mean of its divisors is an integer number (18265107).

Almost surely, 2^816589920 is an apocalyptic number.

816589920 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 816589920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1315087704).

816589920 is an abundant number, since it is smaller than the sum of its proper divisors (1813585488).

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

816589920 is a wasteful number, since it uses less digits than its factorization.

816589920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 413 (or 238 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 48.

The square root of 816589920 is about 28576.0375139731. The cubic root of 816589920 is about 934.6908793488.

The spelling of 816589920 in words is "eight hundred sixteen million, five hundred eighty-nine thousand, nine hundred twenty".