13151221 has 4 divisors (see below), whose sum is σ = 13251744. Its totient is φ = 13050700.

The previous prime is 13151197. The next prime is 13151227. The reversal of 13151221 is 12215131.

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 13151221 - 2⁵ = 13151189 is a prime.

It is a super-2 number, since 2×13151221² = 345909227581682, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 13151195 and 13151204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13151227) 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, 50065 + ... + 50326.

It is an arithmetic number, because the mean of its divisors is an integer number (3312936).

Almost surely, 2^13151221 is an apocalyptic number.

It is an amenable number.

13151221 is a deficient number, since it is larger than the sum of its proper divisors (100523).

13151221 is a wasteful number, since it uses less digits than its factorization.

13151221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100522.

The product of its digits is 60, while the sum is 16.

The square root of 13151221 is about 3626.4612227349. The cubic root of 13151221 is about 236.0416772607.

Adding to 13151221 its reverse (12215131), we get a palindrome (25366352).

The spelling of 13151221 in words is "thirteen million, one hundred fifty-one thousand, two hundred twenty-one".