8637289721 has 4 divisors (see below), whose sum is σ = 8647734672. Its totient is φ = 8626844772.

The previous prime is 8637289691. The next prime is 8637289741. The reversal of 8637289721 is 1279827368.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8637289721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8637289741) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5221235 + ... + 5222888.

It is an arithmetic number, because the mean of its divisors is an integer number (2161933668).

Almost surely, 2^8637289721 is an apocalyptic number.

It is an amenable number.

8637289721 is a deficient number, since it is larger than the sum of its proper divisors (10444951).

8637289721 is a wasteful number, since it uses less digits than its factorization.

8637289721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10444950.

The product of its digits is 2032128, while the sum is 53.

The square root of 8637289721 is about 92937.0201857150. The cubic root of 8637289721 is about 2051.7565528369.

The spelling of 8637289721 in words is "eight billion, six hundred thirty-seven million, two hundred eighty-nine thousand, seven hundred twenty-one".