639719 has 2 divisors, whose sum is σ = 639720. Its totient is φ = 639718.

The previous prime is 639713. The next prime is 639731. The reversal of 639719 is 917936.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 639719 - 2⁴ = 639703 is a prime.

It is a super-2 number, since 2×639719² = 818480797922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639713) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319859 + 319860.

It is an arithmetic number, because the mean of its divisors is an integer number (319860).

2⁶³⁹⁷¹⁹ is an apocalyptic number.

639719 is a deficient number, since it is larger than the sum of its proper divisors (1).

639719 is an equidigital number, since it uses as much as digits as its factorization.

639719 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10206, while the sum is 35.

The square root of 639719 is about 799.8243557182. The cubic root of 639719 is about 86.1647733352.

The spelling of 639719 in words is "six hundred thirty-nine thousand, seven hundred nineteen".