639983 has 2 divisors, whose sum is σ = 639984. Its totient is φ = 639982.

The previous prime is 639959. The next prime is 639997. The reversal of 639983 is 389936.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 639983 - 2¹⁰ = 638959 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 (639083) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319991 + 319992.

It is an arithmetic number, because the mean of its divisors is an integer number (319992).

2⁶³⁹⁹⁸³ is an apocalyptic number.

639983 is a deficient number, since it is larger than the sum of its proper divisors (1).

639983 is an equidigital number, since it uses as much as digits as its factorization.

639983 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 34992, while the sum is 38.

The square root of 639983 is about 799.9893749294. The cubic root of 639983 is about 86.1766245656.

Subtracting from 639983 its reverse (389936), we obtain a cube (250047 = 63³).

The spelling of 639983 in words is "six hundred thirty-nine thousand, nine hundred eighty-three".