639169 has 2 divisors, whose sum is σ = 639170. Its totient is φ = 639168.

The previous prime is 639167. The next prime is 639181. The reversal of 639169 is 961936.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 620944 + 18225 = 788^2 + 135^2 .

It is a cyclic number.

It is not a de Polignac number, because 639169 - 2¹ = 639167 is a prime.

It is a super-2 number, since 2×639169² = 817074021122, which contains 22 as substring.

Together with 639167, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (639167) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319584 + 319585.

It is an arithmetic number, because the mean of its divisors is an integer number (319585).

2⁶³⁹¹⁶⁹ is an apocalyptic number.

It is an amenable number.

639169 is a deficient number, since it is larger than the sum of its proper divisors (1).

639169 is an equidigital number, since it uses as much as digits as its factorization.

639169 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8748, while the sum is 34.

The square root of 639169 is about 799.4804562965. The cubic root of 639169 is about 86.1400727957.

It can be divided in two parts, 639 and 169, that added together give a palindrome (808).

The spelling of 639169 in words is "six hundred thirty-nine thousand, one hundred sixty-nine".