131221117 has 2 divisors, whose sum is σ = 131221118. Its totient is φ = 131221116.

The previous prime is 131221093. The next prime is 131221121. The reversal of 131221117 is 711122131.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 130622041 + 599076 = 11429^2 + 774^2 .

It is an emirp because it is prime and its reverse (711122131) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 131221117 - 2⁷ = 131220989 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 131221094 and 131221103.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (131221177) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65610558 + 65610559.

It is an arithmetic number, because the mean of its divisors is an integer number (65610559).

Almost surely, 2^131221117 is an apocalyptic number.

It is an amenable number.

131221117 is a deficient number, since it is larger than the sum of its proper divisors (1).

131221117 is an equidigital number, since it uses as much as digits as its factorization.

131221117 is an evil number, because the sum of its binary digits is even.

The product of its digits is 84, while the sum is 19.

The square root of 131221117 is about 11455.1786105674. The cubic root of 131221117 is about 508.1608974809.

Adding to 131221117 its reverse (711122131), we get a palindrome (842343248).

The spelling of 131221117 in words is "one hundred thirty-one million, two hundred twenty-one thousand, one hundred seventeen".