13979909 has 4 divisors (see below), whose sum is σ = 14027916. Its totient is φ = 13931904.

The previous prime is 13979857. The next prime is 13979921. The reversal of 13979909 is 90997931.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 7579009 + 6400900 = 2753^2 + 2530^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13979909 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13979209) 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, 23564 + ... + 24149.

It is an arithmetic number, because the mean of its divisors is an integer number (3506979).

Almost surely, 2^13979909 is an apocalyptic number.

It is an amenable number.

13979909 is a deficient number, since it is larger than the sum of its proper divisors (48007).

13979909 is an equidigital number, since it uses as much as digits as its factorization.

13979909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48006.

The product of its (nonzero) digits is 137781, while the sum is 47.

The square root of 13979909 is about 3738.9716500664. The cubic root of 13979909 is about 240.8988803466.

The spelling of 13979909 in words is "thirteen million, nine hundred seventy-nine thousand, nine hundred nine".