13218639 has 32 divisors (see below), whose sum is σ = 21712896. Its totient is φ = 6981120.

The previous prime is 13218619. The next prime is 13218649. The reversal of 13218639 is 93681231.

It is not a de Polignac number, because 13218639 - 2⁵ = 13218607 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13218619) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 21474 + ... + 22080.

It is an arithmetic number, because the mean of its divisors is an integer number (678528).

Almost surely, 2^13218639 is an apocalyptic number.

13218639 is a deficient number, since it is larger than the sum of its proper divisors (8494257).

13218639 is a wasteful number, since it uses less digits than its factorization.

13218639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 695.

The product of its digits is 7776, while the sum is 33.

The square root of 13218639 is about 3635.7446279958. The cubic root of 13218639 is about 236.4443354937. Note that the first 3 decimals are identical.

The spelling of 13218639 in words is "thirteen million, two hundred eighteen thousand, six hundred thirty-nine".