129599999 has 4 divisors (see below), whose sum is σ = 132045336. Its totient is φ = 127154664.

The previous prime is 129599983. The next prime is 129600001. The reversal of 129599999 is 999995921.

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

It is a cyclic number.

It is not a de Polignac number, because 129599999 - 2⁴ = 129599983 is a prime.

It is a Duffinian number.

129599999 is a modest number, since divided by 99999 gives 1295 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129599699) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1222589 + ... + 1222694.

It is an arithmetic number, because the mean of its divisors is an integer number (33011334).

Almost surely, 2^129599999 is an apocalyptic number.

129599999 is a deficient number, since it is larger than the sum of its proper divisors (2445337).

129599999 is an equidigital number, since it uses as much as digits as its factorization.

129599999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2445336.

The product of its digits is 5314410, while the sum is 62.

The square root of 129599999 is about 11384.1995326856. The cubic root of 129599999 is about 506.0595978795.

The spelling of 129599999 in words is "one hundred twenty-nine million, five hundred ninety-nine thousand, nine hundred ninety-nine".