131115661 has 2 divisors, whose sum is σ = 131115662. Its totient is φ = 131115660.

The previous prime is 131115653. The next prime is 131115667. The reversal of 131115661 is 166511131.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 125014761 + 6100900 = 11181^2 + 2470^2 .

It is a cyclic number.

It is not a de Polignac number, because 131115661 - 2³ = 131115653 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (131115667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65557830 + 65557831.

It is an arithmetic number, because the mean of its divisors is an integer number (65557831).

Almost surely, 2^131115661 is an apocalyptic number.

It is an amenable number.

131115661 is a deficient number, since it is larger than the sum of its proper divisors (1).

131115661 is an equidigital number, since it uses as much as digits as its factorization.

131115661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 540, while the sum is 25.

The square root of 131115661 is about 11450.5747017344. The cubic root of 131115661 is about 508.0247329703.

Adding to 131115661 its reverse (166511131), we get a palindrome (297626792).

The spelling of 131115661 in words is "one hundred thirty-one million, one hundred fifteen thousand, six hundred sixty-one".