639542 has 8 divisors (see below), whose sum is σ = 967032. Its totient is φ = 317200.

The previous prime is 639533. The next prime is 639547. The reversal of 639542 is 245936.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639547) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 959 + ... + 1482.

It is an arithmetic number, because the mean of its divisors is an integer number (120879).

2⁶³⁹⁵⁴² is an apocalyptic number.

639542 is a deficient number, since it is larger than the sum of its proper divisors (327490).

639542 is a wasteful number, since it uses less digits than its factorization.

639542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2574.

The product of its digits is 6480, while the sum is 29.

The square root of 639542 is about 799.7136987698. The cubic root of 639542 is about 86.1568257980.

The spelling of 639542 in words is "six hundred thirty-nine thousand, five hundred forty-two".