623639 has 4 divisors (see below), whose sum is σ = 632256. Its totient is φ = 615024.

The previous prime is 623633. The next prime is 623641. The reversal of 623639 is 936326.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 623639 - 2⁸ = 623383 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (623633) 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, 4199 + ... + 4344.

It is an arithmetic number, because the mean of its divisors is an integer number (158064).

2⁶²³⁶³⁹ is an apocalyptic number.

623639 is a deficient number, since it is larger than the sum of its proper divisors (8617).

623639 is an equidigital number, since it uses as much as digits as its factorization.

623639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8616.

The product of its digits is 5832, while the sum is 29.

The square root of 623639 is about 789.7081739478. The cubic root of 623639 is about 85.4366915044.

The spelling of 623639 in words is "six hundred twenty-three thousand, six hundred thirty-nine".