13638399 has 4 divisors (see below), whose sum is σ = 18184536. Its totient is φ = 9092264.

The previous prime is 13638397. The next prime is 13638421. The reversal of 13638399 is 99383631.

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 13638399 - 2¹ = 13638397 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 13638399.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13638397) 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, 2273064 + ... + 2273069.

It is an arithmetic number, because the mean of its divisors is an integer number (4546134).

Almost surely, 2^13638399 is an apocalyptic number.

13638399 is a deficient number, since it is larger than the sum of its proper divisors (4546137).

13638399 is an equidigital number, since it uses as much as digits as its factorization.

13638399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4546136.

The product of its digits is 104976, while the sum is 42.

The square root of 13638399 is about 3693.0203086363. The cubic root of 13638399 is about 238.9210770961.

The spelling of 13638399 in words is "thirteen million, six hundred thirty-eight thousand, three hundred ninety-nine".