639042 has 16 divisors (see below), whose sum is σ = 1296480. Its totient is φ = 209952.

The previous prime is 639011. The next prime is 639043. The reversal of 639042 is 240936.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (639043) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 292 + ... + 1167.

It is an arithmetic number, because the mean of its divisors is an integer number (81030).

2⁶³⁹⁰⁴² is an apocalyptic number.

639042 is an abundant number, since it is smaller than the sum of its proper divisors (657438).

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

639042 is a wasteful number, since it uses less digits than its factorization.

639042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1537.

The product of its (nonzero) digits is 1296, while the sum is 24.

The square root of 639042 is about 799.4010257687. The cubic root of 639042 is about 86.1343672031.

Adding to 639042 its reverse (240936), we get a palindrome (879978).

The spelling of 639042 in words is "six hundred thirty-nine thousand, forty-two".