13231221 has 8 divisors (see below), whose sum is σ = 18250080. Its totient is φ = 8516592.

The previous prime is 13231189. The next prime is 13231247. The reversal of 13231221 is 12213231.

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

It is not a de Polignac number, because 13231221 - 2⁵ = 13231189 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 13231221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13231261) 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 7 ways as a sum of consecutive naturals, for example, 75955 + ... + 76128.

It is an arithmetic number, because the mean of its divisors is an integer number (2281260).

Almost surely, 2^13231221 is an apocalyptic number.

It is an amenable number.

13231221 is a deficient number, since it is larger than the sum of its proper divisors (5018859).

13231221 is a wasteful number, since it uses less digits than its factorization.

13231221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152115.

The product of its digits is 72, while the sum is 15.

The square root of 13231221 is about 3637.4745359933. The cubic root of 13231221 is about 236.5193305882.

Adding to 13231221 its reverse (12213231), we get a palindrome (25444452).

The spelling of 13231221 in words is "thirteen million, two hundred thirty-one thousand, two hundred twenty-one".