639001 has 6 divisors (see below), whose sum is σ = 702506. Its totient is φ = 580800.

The previous prime is 638999. The next prime is 639007. The reversal of 639001 is 100936.

639001 = 236² + 237² + ... + 246².

It can be written as a sum of positive squares in only one way, i.e., 435600 + 203401 = 660^2 + 451^2 .

It is not a de Polignac number, because 639001 - 2¹ = 638999 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 639001.

It is not an unprimeable number, because it can be changed into a prime (639007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2520 + ... + 2761.

2⁶³⁹⁰⁰¹ is an apocalyptic number.

It is an amenable number.

639001 is a deficient number, since it is larger than the sum of its proper divisors (63505).

639001 is a wasteful number, since it uses less digits than its factorization.

639001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5303 (or 5292 counting only the distinct ones).

The product of its (nonzero) digits is 162, while the sum is 19.

The square root of 639001 is about 799.3753811571. The cubic root of 639001 is about 86.1325250787.

Adding to 639001 its reverse (100936), we get a palindrome (739937).

The spelling of 639001 in words is "six hundred thirty-nine thousand, one".