129995681 has 4 divisors (see below), whose sum is σ = 130215492. Its totient is φ = 129775872.

The previous prime is 129995669. The next prime is 129995683. The reversal of 129995681 is 186599921.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 41165056 + 88830625 = 6416^2 + 9425^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-129995681 is a prime.

It is a super-2 number, since 2×129995681² = 33797754157307522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (129995683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 109016 + ... + 110201.

It is an arithmetic number, because the mean of its divisors is an integer number (32553873).

Almost surely, 2^129995681 is an apocalyptic number.

It is an amenable number.

129995681 is a deficient number, since it is larger than the sum of its proper divisors (219811).

129995681 is an equidigital number, since it uses as much as digits as its factorization.

129995681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 219810.

The product of its digits is 349920, while the sum is 50.

The square root of 129995681 is about 11401.5648487390. The cubic root of 129995681 is about 506.5740918025.

The spelling of 129995681 in words is "one hundred twenty-nine million, nine hundred ninety-five thousand, six hundred eighty-one".