13671221 has 4 divisors (see below), whose sum is σ = 13858572. Its totient is φ = 13483872.

The previous prime is 13671193. The next prime is 13671227. The reversal of 13671221 is 12217631.

13671221 = 2614² + 2615².

13671221 is digitally balanced in base 2, 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 an emirpimes, since its reverse is a distinct semiprime: 12217631 = 41 ⋅297991.

It can be written as a sum of positive squares in 2 ways, for example, as 6838225 + 6832996 = 2615^2 + 2614^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13671221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13671227) 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, 93566 + ... + 93711.

It is an arithmetic number, because the mean of its divisors is an integer number (3464643).

Almost surely, 2^13671221 is an apocalyptic number.

13671221 is the 2615-th centered square number.

It is an amenable number.

13671221 is a deficient number, since it is larger than the sum of its proper divisors (187351).

13671221 is an equidigital number, since it uses as much as digits as its factorization.

13671221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187350.

The product of its digits is 504, while the sum is 23.

The square root of 13671221 is about 3697.4614264384. The cubic root of 13671221 is about 239.1125850406.

Adding to 13671221 its reverse (12217631), we get a palindrome (25888852).

The spelling of 13671221 in words is "thirteen million, six hundred seventy-one thousand, two hundred twenty-one".