131221229 has 2 divisors, whose sum is σ = 131221230. Its totient is φ = 131221228.

The previous prime is 131221213. The next prime is 131221231. The reversal of 131221229 is 922122131.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 93644329 + 37576900 = 9677^2 + 6130^2 .

It is a cyclic number.

It is not a de Polignac number, because 131221229 - 2⁴ = 131221213 is a prime.

It is a super-3 number, since 3×131221229³ (a number of 25 digits) contains 333 as substring.

Together with 131221231, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (131221289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65610614 + 65610615.

It is an arithmetic number, because the mean of its divisors is an integer number (65610615).

Almost surely, 2^131221229 is an apocalyptic number.

It is an amenable number.

131221229 is a deficient number, since it is larger than the sum of its proper divisors (1).

131221229 is an equidigital number, since it uses as much as digits as its factorization.

131221229 is an evil number, because the sum of its binary digits is even.

The product of its digits is 432, while the sum is 23.

The square root of 131221229 is about 11455.1834991850. The cubic root of 131221229 is about 508.1610420562.

It can be divided in two parts, 13122122 and 9, that added together give a palindrome (13122131).

The spelling of 131221229 in words is "one hundred thirty-one million, two hundred twenty-one thousand, two hundred twenty-nine".