816599556 has 192 divisors, whose sum is σ = 2397024000. Its totient is φ = 242704512.

The previous prime is 816599549. The next prime is 816599587. The reversal of 816599556 is 655995618.

816599556 is a `hidden beast` number, since 81 + 6 + 5 + 9 + 9 + 556 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

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, 42978915 + ... + 42978933.

It is an arithmetic number, because the mean of its divisors is an integer number (12484500).

Almost surely, 2^816599556 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 816599556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1198512000).

816599556 is an abundant number, since it is smaller than the sum of its proper divisors (1580424444).

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

816599556 is an equidigital number, since it uses as much as digits as its factorization.

816599556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95 (or 41 counting only the distinct ones).

The product of its digits is 2916000, while the sum is 54.

The square root of 816599556 is about 28576.2061162779. The cubic root of 816599556 is about 934.6945558763.

The spelling of 816599556 in words is "eight hundred sixteen million, five hundred ninety-nine thousand, five hundred fifty-six".