639517 has 2 divisors, whose sum is σ = 639518. Its totient is φ = 639516.

The previous prime is 639511. The next prime is 639533. The reversal of 639517 is 715936.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 470596 + 168921 = 686^2 + 411^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-639517 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319758 + 319759.

It is an arithmetic number, because the mean of its divisors is an integer number (319759).

2⁶³⁹⁵¹⁷ is an apocalyptic number.

It is an amenable number.

639517 is a deficient number, since it is larger than the sum of its proper divisors (1).

639517 is an equidigital number, since it uses as much as digits as its factorization.

639517 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5670, while the sum is 31.

The square root of 639517 is about 799.6980680232. The cubic root of 639517 is about 86.1557031463.

It can be divided in two parts, 639 and 517, that added together give a square (1156 = 34²).

The spelling of 639517 in words is "six hundred thirty-nine thousand, five hundred seventeen".