639253169 has 2 divisors, whose sum is σ = 639253170. Its totient is φ = 639253168.

The previous prime is 639253133. The next prime is 639253171. The reversal of 639253169 is 961352936.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 625600144 + 13653025 = 25012^2 + 3695^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-639253169 is a prime.

It is a super-2 number, since 2×639253169² = 817289228153085122, which contains 22 as substring.

Together with 639253171, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (639259169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319626584 + 319626585.

It is an arithmetic number, because the mean of its divisors is an integer number (319626585).

Almost surely, 2^639253169 is an apocalyptic number.

It is an amenable number.

639253169 is a deficient number, since it is larger than the sum of its proper divisors (1).

639253169 is an equidigital number, since it uses as much as digits as its factorization.

639253169 is an evil number, because the sum of its binary digits is even.

The product of its digits is 262440, while the sum is 44.

The square root of 639253169 is about 25283.4564290565. The cubic root of 639253169 is about 861.4385374962.

The spelling of 639253169 in words is "six hundred thirty-nine million, two hundred fifty-three thousand, one hundred sixty-nine".