8644021913 has 2 divisors, whose sum is σ = 8644021914. Its totient is φ = 8644021912.

The previous prime is 8644021891. The next prime is 8644021993. The reversal of 8644021913 is 3191204468.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8412008089 + 232013824 = 91717^2 + 15232^2 .

It is a cyclic number.

It is not a de Polignac number, because 8644021913 - 2²⁰ = 8642973337 is a prime.

It is a super-2 number, since 2×8644021913² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (8644021993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4322010956 + 4322010957.

It is an arithmetic number, because the mean of its divisors is an integer number (4322010957).

Almost surely, 2^8644021913 is an apocalyptic number.

It is an amenable number.

8644021913 is a deficient number, since it is larger than the sum of its proper divisors (1).

8644021913 is an equidigital number, since it uses as much as digits as its factorization.

8644021913 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 41472, while the sum is 38.

The square root of 8644021913 is about 92973.2322391773. The cubic root of 8644021913 is about 2052.2894835874.

The spelling of 8644021913 in words is "eight billion, six hundred forty-four million, twenty-one thousand, nine hundred thirteen".