13681439 has 4 divisors (see below), whose sum is σ = 13999656. Its totient is φ = 13363224.

The previous prime is 13681433. The next prime is 13681469. The reversal of 13681439 is 93418631.

13681439 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13681439 is a prime.

It is a super-2 number, since 2×13681439² = 374363546221442, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 13681399 and 13681408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13681433) 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, 159044 + ... + 159129.

It is an arithmetic number, because the mean of its divisors is an integer number (3499914).

Almost surely, 2^13681439 is an apocalyptic number.

13681439 is a deficient number, since it is larger than the sum of its proper divisors (318217).

13681439 is an equidigital number, since it uses as much as digits as its factorization.

13681439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 318216.

The product of its digits is 15552, while the sum is 35.

The square root of 13681439 is about 3698.8429271868. The cubic root of 13681439 is about 239.1721418752.

The spelling of 13681439 in words is "thirteen million, six hundred eighty-one thousand, four hundred thirty-nine".