639329 has 2 divisors, whose sum is σ = 639330. Its totient is φ = 639328.

The previous prime is 639311. The next prime is 639337. The reversal of 639329 is 923936.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 616225 + 23104 = 785^2 + 152^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-639329 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 639295 and 639304.

It is not a weakly prime, because it can be changed into another prime (632329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319664 + 319665.

It is an arithmetic number, because the mean of its divisors is an integer number (319665).

2⁶³⁹³²⁹ is an apocalyptic number.

It is an amenable number.

639329 is a deficient number, since it is larger than the sum of its proper divisors (1).

639329 is an equidigital number, since it uses as much as digits as its factorization.

639329 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8748, while the sum is 32.

The square root of 639329 is about 799.5805150202. The cubic root of 639329 is about 86.1472598682.

The spelling of 639329 in words is "six hundred thirty-nine thousand, three hundred twenty-nine".