816990720 has 480 divisors, whose sum is σ = 3291539328. Its totient is φ = 171343872.

The previous prime is 816990703. The next prime is 816990773. The reversal of 816990720 is 27099618.

It is a tau number, because it is divible by the number of its divisors (480).

It is a super-2 number, since 2×816990720² = 1334947673132236800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

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, 4892077 + ... + 4892243.

Almost surely, 2^816990720 is an apocalyptic number.

816990720 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 816990720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1645769664).

816990720 is an abundant number, since it is smaller than the sum of its proper divisors (2474548608).

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

816990720 is a wasteful number, since it uses less digits than its factorization.

816990720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220 (or 197 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 42.

The square root of 816990720 is about 28583.0495224005. The cubic root of 816990720 is about 934.8437765051.

It can be divided in two parts, 8169 and 90720, that added together give a palindrome (98889).

The spelling of 816990720 in words is "eight hundred sixteen million, nine hundred ninety thousand, seven hundred twenty".