639113221 has 2 divisors, whose sum is σ = 639113222. Its totient is φ = 639113220.

The previous prime is 639113219. The next prime is 639113227. The reversal of 639113221 is 122311936.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 514790721 + 124322500 = 22689^2 + 11150^2 .

It is a cyclic number.

It is not a de Polignac number, because 639113221 - 2¹ = 639113219 is a prime.

It is a super-3 number, since 3×639113221³ (a number of 27 digits) contains 333 as substring.

Together with 639113219, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 639113221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639113227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319556610 + 319556611.

It is an arithmetic number, because the mean of its divisors is an integer number (319556611).

Almost surely, 2^639113221 is an apocalyptic number.

It is an amenable number.

639113221 is a deficient number, since it is larger than the sum of its proper divisors (1).

639113221 is an equidigital number, since it uses as much as digits as its factorization.

639113221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1944, while the sum is 28.

The square root of 639113221 is about 25280.6886971063. The cubic root of 639113221 is about 861.3756696555.

The spelling of 639113221 in words is "six hundred thirty-nine million, one hundred thirteen thousand, two hundred twenty-one".