129205573657 has 2 divisors, whose sum is σ = 129205573658. Its totient is φ = 129205573656.

The previous prime is 129205573547. The next prime is 129205573663. The reversal of 129205573657 is 756375502921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 113199275401 + 16006298256 = 336451^2 + 126516^2 .

It is an emirp because it is prime and its reverse (756375502921) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 129205573657 - 2¹¹ = 129205571609 is a prime.

It is not a weakly prime, because it can be changed into another prime (129205573667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64602786828 + 64602786829.

It is an arithmetic number, because the mean of its divisors is an integer number (64602786829).

Almost surely, 2^129205573657 is an apocalyptic number.

It is an amenable number.

129205573657 is a deficient number, since it is larger than the sum of its proper divisors (1).

129205573657 is an equidigital number, since it uses as much as digits as its factorization.

129205573657 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3969000, while the sum is 52.

The spelling of 129205573657 in words is "one hundred twenty-nine billion, two hundred five million, five hundred seventy-three thousand, six hundred fifty-seven".