816621388800 has 528 divisors, whose sum is σ = 3093696276480. Its totient is φ = 186102743040.

The previous prime is 816621388789. The next prime is 816621388819. The reversal of 816621388800 is 8883126618.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 197297131 + ... + 197301269.

Almost surely, 2^816621388800 is an apocalyptic number.

816621388800 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 816621388800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1546848138240).

816621388800 is an abundant number, since it is smaller than the sum of its proper divisors (2277074887680).

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

816621388800 is a wasteful number, since it uses less digits than its factorization.

816621388800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4546 (or 4523 counting only the distinct ones).

The product of its (nonzero) digits is 884736, while the sum is 51.

The spelling of 816621388800 in words is "eight hundred sixteen billion, six hundred twenty-one million, three hundred eighty-eight thousand, eight hundred".