13831921 has 4 divisors (see below), whose sum is σ = 14278144. Its totient is φ = 13385700.

The previous prime is 13831919. The next prime is 13831957. The reversal of 13831921 is 12913831.

13831921 is digitally balanced in base 3, 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 13831921 - 2¹ = 13831919 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 13831921.

It is not an unprimeable number, because it can be changed into a prime (13831121) 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, 223065 + ... + 223126.

It is an arithmetic number, because the mean of its divisors is an integer number (3569536).

Almost surely, 2^13831921 is an apocalyptic number.

It is an amenable number.

13831921 is a deficient number, since it is larger than the sum of its proper divisors (446223).

13831921 is an equidigital number, since it uses as much as digits as its factorization.

13831921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 446222.

The product of its digits is 1296, while the sum is 28.

The square root of 13831921 is about 3719.1290647139. The cubic root of 13831921 is about 240.0458303681.

The spelling of 13831921 in words is "thirteen million, eight hundred thirty-one thousand, nine hundred twenty-one".