13381221 has 8 divisors (see below), whose sum is σ = 20390464. Its totient is φ = 7646400.

The previous prime is 13381217. The next prime is 13381231. The reversal of 13381221 is 12218331.

13381221 is digitally balanced in base 2, base 4 and base 8, because in such bases it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 13381221 - 2² = 13381217 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 637201 = 13381221 / (1 + 3 + 3 + 8 + 1 + 2 + 2 + 1).

It is a Duffinian number.

13381221 is strictly pandigital in base 8.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13381231) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 318580 + ... + 318621.

It is an arithmetic number, because the mean of its divisors is an integer number (2548808).

Almost surely, 2^13381221 is an apocalyptic number.

It is an amenable number.

13381221 is a deficient number, since it is larger than the sum of its proper divisors (7009243).

13381221 is an equidigital number, since it uses as much as digits as its factorization.

13381221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 637211.

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

The square root of 13381221 is about 3658.0351283168. The cubic root of 13381221 is about 237.4097666454.

Adding to 13381221 its reverse (12218331), we get a palindrome (25599552).

The spelling of 13381221 in words is "thirteen million, three hundred eighty-one thousand, two hundred twenty-one".