639243 has 18 divisors (see below), whose sum is σ = 1016652. Its totient is φ = 386760.

The previous prime is 639211. The next prime is 639253. The reversal of 639243 is 342936.

639243 is a `hidden beast` number, since 639 + 24 + 3 = 666.

It is not a de Polignac number, because 639243 - 2⁵ = 639211 is a prime.

It is a super-2 number, since 2×639243² = 817263226098, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (639253) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 796 + ... + 1382.

2⁶³⁹²⁴³ is an apocalyptic number.

639243 is a deficient number, since it is larger than the sum of its proper divisors (377409).

639243 is a wasteful number, since it uses less digits than its factorization.

639243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 615 (or 601 counting only the distinct ones).

The product of its digits is 3888, while the sum is 27.

The square root of 639243 is about 799.5267350127. The cubic root of 639243 is about 86.1433969658.

The spelling of 639243 in words is "six hundred thirty-nine thousand, two hundred forty-three".