129991688 has 36 divisors (see below), whose sum is σ = 254257965. Its totient is φ = 62303136.

The previous prime is 129991663. The next prime is 129991703. The reversal of 129991688 is 886199921.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 2 ways, for example, as 129914404 + 77284 = 11398^2 + 278^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=8062.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 935123 + ... + 935261.

Almost surely, 2^129991688 is an apocalyptic number.

It is an amenable number.

129991688 is a deficient number, since it is larger than the sum of its proper divisors (124266277).

129991688 is an equidigital number, since it uses as much as digits as its factorization.

129991688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342 (or 170 counting only the distinct ones).

The product of its digits is 559872, while the sum is 53.

The square root of 129991688 is about 11401.3897398519. The cubic root of 129991688 is about 506.5689050377.

The spelling of 129991688 in words is "one hundred twenty-nine million, nine hundred ninety-one thousand, six hundred eighty-eight".