129161520255625 has 375 divisors, whose sum is σ = 204261807732015. Its totient is φ = 81609253440000.

The previous prime is 129161520255613. The next prime is 129161520255641. The reversal of 129161520255625 is 526552025161921.

The square root of 129161520255625 is 11364925.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 37 ways, for example, as 53843352866809 + 75318167388816 = 7337803^2 + 8678604^2 .

It is a de Polignac number, because none of the positive numbers 2^k-129161520255625 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 374 ways as a sum of consecutive naturals, for example, 7597736485617 + ... + 7597736485633.

Almost surely, 2^{129161520255625} is an apocalyptic number.

129161520255625 is the 11364925-th square number.

129161520255625 is the 5682463-rd centered octagonal number.

It is an amenable number.

129161520255625 is a deficient number, since it is larger than the sum of its proper divisors (75100287476390).

129161520255625 is an frugal number, since it uses more digits than its factorization.

129161520255625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158 (or 46 counting only the distinct ones).

The product of its (nonzero) digits is 3240000, while the sum is 52.

The spelling of 129161520255625 in words is "one hundred twenty-nine trillion, one hundred sixty-one billion, five hundred twenty million, two hundred fifty-five thousand, six hundred twenty-five".