816645320568 has 384 divisors, whose sum is σ = 2880948902400. Its totient is φ = 211950950400.

The previous prime is 816645320443. The next prime is 816645320593. The reversal of 816645320568 is 865023546618.

816645320568 is a `hidden beast` number, since 8 + 1 + 6 + 6 + 4 + 53 + 20 + 568 = 666.

It is a super-2 number, since 2×816645320568² (a number of 25 digits) contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 242975208 + ... + 242978568.

It is an arithmetic number, because the mean of its divisors is an integer number (7502471100).

Almost surely, 2^816645320568 is an apocalyptic number.

816645320568 is a gapful number since it is divisible by the number (88) 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 816645320568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1440474451200).

816645320568 is an abundant number, since it is smaller than the sum of its proper divisors (2064303581832).

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

816645320568 is a wasteful number, since it uses less digits than its factorization.

816645320568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5488 (or 5471 counting only the distinct ones).

The product of its (nonzero) digits is 8294400, while the sum is 54.

The spelling of 816645320568 in words is "eight hundred sixteen billion, six hundred forty-five million, three hundred twenty thousand, five hundred sixty-eight".