639571 has 2 divisors, whose sum is σ = 639572. Its totient is φ = 639570.

The previous prime is 639563. The next prime is 639577. The reversal of 639571 is 175936.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 639571 - 2³ = 639563 is a prime.

It is not a weakly prime, because it can be changed into another prime (639577) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319785 + 319786.

It is an arithmetic number, because the mean of its divisors is an integer number (319786).

2⁶³⁹⁵⁷¹ is an apocalyptic number.

639571 is a deficient number, since it is larger than the sum of its proper divisors (1).

639571 is an equidigital number, since it uses as much as digits as its factorization.

639571 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 639571 is about 799.7318300530. The cubic root of 639571 is about 86.1581280373.

The spelling of 639571 in words is "six hundred thirty-nine thousand, five hundred seventy-one".