13857681 has 4 divisors (see below), whose sum is σ = 18476912. Its totient is φ = 9238452.

The previous prime is 13857667. The next prime is 13857691. The reversal of 13857681 is 18675831.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 13857681 - 2⁶ = 13857617 is a prime.

It is a super-2 number, since 2×13857681² = 384070645395522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13857691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2309611 + ... + 2309616.

It is an arithmetic number, because the mean of its divisors is an integer number (4619228).

Almost surely, 2^13857681 is an apocalyptic number.

It is an amenable number.

13857681 is a deficient number, since it is larger than the sum of its proper divisors (4619231).

13857681 is an equidigital number, since it uses as much as digits as its factorization.

13857681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4619230.

The product of its digits is 40320, while the sum is 39.

The square root of 13857681 is about 3722.5906301929. The cubic root of 13857681 is about 240.1947551119.

The spelling of 13857681 in words is "thirteen million, eight hundred fifty-seven thousand, six hundred eighty-one".