639633 has 8 divisors (see below), whose sum is σ = 861696. Its totient is φ = 422000.

The previous prime is 639631. The next prime is 639637. The reversal of 639633 is 336936.

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

It is a cyclic number.

It is not a de Polignac number, because 639633 - 2¹ = 639631 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 639633.

It is not an unprimeable number, because it can be changed into a prime (639631) 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, 753 + ... + 1358.

It is an arithmetic number, because the mean of its divisors is an integer number (107712).

2⁶³⁹⁶³³ is an apocalyptic number.

It is an amenable number.

639633 is a deficient number, since it is larger than the sum of its proper divisors (222063).

639633 is a wasteful number, since it uses less digits than its factorization.

639633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2215.

The product of its digits is 8748, while the sum is 30.

The square root of 639633 is about 799.7705921075. The cubic root of 639633 is about 86.1609120031.

The spelling of 639633 in words is "six hundred thirty-nine thousand, six hundred thirty-three".