131210221 has 2 divisors, whose sum is σ = 131210222. Its totient is φ = 131210220.

The previous prime is 131210213. The next prime is 131210237. The reversal of 131210221 is 122012131.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 130188100 + 1022121 = 11410^2 + 1011^2 .

It is an emirp because it is prime and its reverse (122012131) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 131210221 - 2³ = 131210213 is a prime.

It is a super-2 number, since 2×131210221² = 34432244189737682, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (131210021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65605110 + 65605111.

It is an arithmetic number, because the mean of its divisors is an integer number (65605111).

Almost surely, 2^131210221 is an apocalyptic number.

It is an amenable number.

131210221 is a deficient number, since it is larger than the sum of its proper divisors (1).

131210221 is an equidigital number, since it uses as much as digits as its factorization.

131210221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 131210221 is about 11454.7030079352. The cubic root of 131210221 is about 508.1468319744.

Adding to 131210221 its reverse (122012131), we get a palindrome (253222352).

The spelling of 131210221 in words is "one hundred thirty-one million, two hundred ten thousand, two hundred twenty-one".