639018 has 24 divisors (see below), whose sum is σ = 1400256. Its totient is φ = 210600.

The previous prime is 639011. The next prime is 639043. The reversal of 639018 is 810936.

It is a junction number, because it is equal to n+sod(n) for n = 638982 and 639000.

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 11 ways as a sum of consecutive naturals, for example, 2223 + ... + 2493.

It is an arithmetic number, because the mean of its divisors is an integer number (58344).

2⁶³⁹⁰¹⁸ is an apocalyptic number.

639018 is an abundant number, since it is smaller than the sum of its proper divisors (761238).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

639018 is a wasteful number, since it uses less digits than its factorization.

639018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 410 (or 407 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 639018 is about 799.3860143885. The cubic root of 639018 is about 86.1332888959.

The spelling of 639018 in words is "six hundred thirty-nine thousand, eighteen".