639013 has 4 divisors (see below), whose sum is σ = 676620. Its totient is φ = 601408.

The previous prime is 639011. The next prime is 639043. The reversal of 639013 is 310936.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 465124 + 173889 = 682^2 + 417^2 .

It is a cyclic number.

It is not a de Polignac number, because 639013 - 2¹ = 639011 is a prime.

It is a super-2 number, since 2×639013² = 816675228338, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639011) 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 3 ways as a sum of consecutive naturals, for example, 18778 + ... + 18811.

It is an arithmetic number, because the mean of its divisors is an integer number (169155).

2⁶³⁹⁰¹³ is an apocalyptic number.

It is an amenable number.

639013 is a deficient number, since it is larger than the sum of its proper divisors (37607).

639013 is a wasteful number, since it uses less digits than its factorization.

639013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37606.

The product of its (nonzero) digits is 486, while the sum is 22.

The square root of 639013 is about 799.3828869822. The cubic root of 639013 is about 86.1330642452.

Adding to 639013 its reverse (310936), we get a palindrome (949949).

The spelling of 639013 in words is "six hundred thirty-nine thousand, thirteen".