639137269 has 2 divisors, whose sum is σ = 639137270. Its totient is φ = 639137268.

The previous prime is 639137263. The next prime is 639137299. The reversal of 639137269 is 962731936.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 473062500 + 166074769 = 21750^2 + 12887^2 .

It is a cyclic number.

It is not a de Polignac number, because 639137269 - 2⁷ = 639137141 is a prime.

It is a super-2 number, since 2×639137269² = 816992897249556722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639137263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319568634 + 319568635.

It is an arithmetic number, because the mean of its divisors is an integer number (319568635).

Almost surely, 2^639137269 is an apocalyptic number.

It is an amenable number.

639137269 is a deficient number, since it is larger than the sum of its proper divisors (1).

639137269 is an equidigital number, since it uses as much as digits as its factorization.

639137269 is an evil number, because the sum of its binary digits is even.

The product of its digits is 367416, while the sum is 46.

The square root of 639137269 is about 25281.1643125866. The cubic root of 639137269 is about 861.3864732198.

It can be divided in two parts, 6391 and 37269, that added together give a triangular number (43660 = T₂₉₅).

The spelling of 639137269 in words is "six hundred thirty-nine million, one hundred thirty-seven thousand, two hundred sixty-nine".