131111221 has 2 divisors, whose sum is σ = 131111222. Its totient is φ = 131111220.

The previous prime is 131111207. The next prime is 131111243. The reversal of 131111221 is 122111131.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 126315121 + 4796100 = 11239^2 + 2190^2 .

It is an emirp because it is prime and its reverse (122111131) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 131111221 - 2⁷ = 131111093 is a prime.

It is a super-2 number, since 2×131111221² = 34380304544221682, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (131111251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65555610 + 65555611.

It is an arithmetic number, because the mean of its divisors is an integer number (65555611).

Almost surely, 2^131111221 is an apocalyptic number.

It is an amenable number.

131111221 is a deficient number, since it is larger than the sum of its proper divisors (1).

131111221 is an equidigital number, since it uses as much as digits as its factorization.

131111221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12, while the sum is 13.

The square root of 131111221 is about 11450.3808233613. The cubic root of 131111221 is about 508.0189984525.

Adding to 131111221 its reverse (122111131), we get a palindrome (253222352).

The spelling of 131111221 in words is "one hundred thirty-one million, one hundred eleven thousand, two hundred twenty-one".