13221381 has 4 divisors (see below), whose sum is σ = 17628512. Its totient is φ = 8814252.

The previous prime is 13221379. The next prime is 13221401. The reversal of 13221381 is 18312231.

13221381 is digitally balanced in base 2 and base 4, because in such bases 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 not a de Polignac number, because 13221381 - 2¹ = 13221379 is a prime.

It is a super-2 number, since 2×13221381² = 349609831094322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13221581) 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, 2203561 + ... + 2203566.

It is an arithmetic number, because the mean of its divisors is an integer number (4407128).

Almost surely, 2^13221381 is an apocalyptic number.

It is an amenable number.

13221381 is a deficient number, since it is larger than the sum of its proper divisors (4407131).

13221381 is an equidigital number, since it uses as much as digits as its factorization.

13221381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4407130.

The product of its digits is 288, while the sum is 21.

The square root of 13221381 is about 3636.1216976333. The cubic root of 13221381 is about 236.4606832570.

The spelling of 13221381 in words is "thirteen million, two hundred twenty-one thousand, three hundred eighty-one".