129961817 has 2 divisors, whose sum is σ = 129961818. Its totient is φ = 129961816.

The previous prime is 129961771. The next prime is 129961829. The reversal of 129961817 is 718169921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 99281296 + 30680521 = 9964^2 + 5539^2 .

It is a cyclic number.

It is not a de Polignac number, because 129961817 - 2²⁰ = 128913241 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (129961217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64980908 + 64980909.

It is an arithmetic number, because the mean of its divisors is an integer number (64980909).

Almost surely, 2^129961817 is an apocalyptic number.

It is an amenable number.

129961817 is a deficient number, since it is larger than the sum of its proper divisors (1).

129961817 is an equidigital number, since it uses as much as digits as its factorization.

129961817 is an evil number, because the sum of its binary digits is even.

The product of its digits is 54432, while the sum is 44.

The square root of 129961817 is about 11400.0796927039. The cubic root of 129961817 is about 506.5301003029.

The spelling of 129961817 in words is "one hundred twenty-nine million, nine hundred sixty-one thousand, eight hundred seventeen".