8720208621 has 12 divisors (see below), whose sum is σ = 13030197180. Its totient is φ = 5613007680.

The previous prime is 8720208619. The next prime is 8720208641. The reversal of 8720208621 is 1268020278.

It is a happy number.

8720208621 is a `hidden beast` number, since 8 + 7 + 2 + 0 + 20 + 8 + 621 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 2665656900 + 6054551721 = 51630^2 + 77811^2 .

It is not a de Polignac number, because 8720208621 - 2¹ = 8720208619 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8720208611) 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, 16705120 + ... + 16705641.

It is an arithmetic number, because the mean of its divisors is an integer number (1085849765).

Almost surely, 2^8720208621 is an apocalyptic number.

It is an amenable number.

8720208621 is a deficient number, since it is larger than the sum of its proper divisors (4309988559).

8720208621 is a wasteful number, since it uses less digits than its factorization.

8720208621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33410796 (or 33410793 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 8720208621 is about 93382.0572754745. The cubic root of 8720208621 is about 2058.3013474411.

Adding to 8720208621 its reverse (1268020278), we get a palindrome (9988228899).

The spelling of 8720208621 in words is "eight billion, seven hundred twenty million, two hundred eight thousand, six hundred twenty-one".