639487 has 2 divisors, whose sum is σ = 639488. Its totient is φ = 639486.

The previous prime is 639451. The next prime is 639491. The reversal of 639487 is 784936.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-639487 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (631487) by changing a digit.

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

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319743 + 319744.

It is an arithmetic number, because the mean of its divisors is an integer number (319744).

2⁶³⁹⁴⁸⁷ is an apocalyptic number.

639487 is a deficient number, since it is larger than the sum of its proper divisors (1).

639487 is an equidigital number, since it uses as much as digits as its factorization.

639487 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 37.

The square root of 639487 is about 799.6793107240. The cubic root of 639487 is about 86.1543559257.

It can be divided in two parts, 6 and 39487, that added together give a palindrome (39493).

The spelling of 639487 in words is "six hundred thirty-nine thousand, four hundred eighty-seven".