820631680 has 96 divisors (see below), whose sum is σ = 2156587020. Its totient is φ = 298383360.

The previous prime is 820631627. The next prime is 820631681. The reversal of 820631680 is 86136028.

It can be written as a sum of positive squares in 2 ways, for example, as 710968896 + 109662784 = 26664^2 + 10472^2 .

It is not an unprimeable number, because it can be changed into a prime (820631681) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 72142 + ... + 82738.

Almost surely, 2^820631680 is an apocalyptic number.

820631680 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 820631680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1078293510).

820631680 is an abundant number, since it is smaller than the sum of its proper divisors (1335955340).

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

820631680 is a wasteful number, since it uses less digits than its factorization.

820631680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10638 (or 10615 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 820631680 is about 28646.6696144595. The cubic root of 820631680 is about 936.2304446353.

The spelling of 820631680 in words is "eight hundred twenty million, six hundred thirty-one thousand, six hundred eighty".