131221213 has 2 divisors, whose sum is σ = 131221214. Its totient is φ = 131221212.

The previous prime is 131221193. The next prime is 131221229. The reversal of 131221213 is 312122131.

It is an a-pointer prime, because the next prime (131221229) can be obtained adding 131221213 to its sum of digits (16).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 72897444 + 58323769 = 8538^2 + 7637^2 .

It is a cyclic number.

It is not a de Polignac number, because 131221213 - 2⁹ = 131220701 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (131221313) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65610606 + 65610607.

It is an arithmetic number, because the mean of its divisors is an integer number (65610607).

Almost surely, 2^131221213 is an apocalyptic number.

It is an amenable number.

131221213 is a deficient number, since it is larger than the sum of its proper divisors (1).

131221213 is an equidigital number, since it uses as much as digits as its factorization.

131221213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 72, while the sum is 16.

The square root of 131221213 is about 11455.1828008112. The cubic root of 131221213 is about 508.1610214026.

Adding to 131221213 its reverse (312122131), we get a palindrome (443343344).

The spelling of 131221213 in words is "one hundred thirty-one million, two hundred twenty-one thousand, two hundred thirteen".