129555857 has 2 divisors, whose sum is σ = 129555858. Its totient is φ = 129555856.

The previous prime is 129555821. The next prime is 129555883. The reversal of 129555857 is 758555921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81793936 + 47761921 = 9044^2 + 6911^2 .

It is a cyclic number.

It is not a de Polignac number, because 129555857 - 2¹⁰ = 129554833 is a prime.

It is not a weakly prime, because it can be changed into another prime (129555817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64777928 + 64777929.

It is an arithmetic number, because the mean of its divisors is an integer number (64777929).

Almost surely, 2^129555857 is an apocalyptic number.

It is an amenable number.

129555857 is a deficient number, since it is larger than the sum of its proper divisors (1).

129555857 is an equidigital number, since it uses as much as digits as its factorization.

129555857 is an evil number, because the sum of its binary digits is even.

The product of its digits is 630000, while the sum is 47.

The square root of 129555857 is about 11382.2606278366. The cubic root of 129555857 is about 506.0021364093.

The spelling of 129555857 in words is "one hundred twenty-nine million, five hundred fifty-five thousand, eight hundred fifty-seven".