13639 has 4 divisors (see below), whose sum is σ = 14256. Its totient is φ = 13024.

The previous prime is 13633. The next prime is 13649. The reversal of 13639 is 93631.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93631 = 109 ⋅859.

It is a cyclic number.

It is not a de Polignac number, because 13639 - 2⁹ = 13127 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax 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 (13633) 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, 274 + ... + 319.

It is an arithmetic number, because the mean of its divisors is an integer number (3564).

13639 is a deficient number, since it is larger than the sum of its proper divisors (617).

13639 is an equidigital number, since it uses as much as digits as its factorization.

13639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 616.

The product of its digits is 486, while the sum is 22.

The square root of 13639 is about 116.7861293134. The cubic root of 13639 is about 23.8924586537.

The spelling of 13639 in words is "thirteen thousand, six hundred thirty-nine".