129040009 has 4 divisors (see below), whose sum is σ = 147474304. Its totient is φ = 110605716.

The previous prime is 129040003. The next prime is 129040031. The reversal of 129040009 is 900040921.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 129040009 - 2⁹ = 129039497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129040003) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9217137 + ... + 9217150.

It is an arithmetic number, because the mean of its divisors is an integer number (36868576).

Almost surely, 2^129040009 is an apocalyptic number.

It is an amenable number.

129040009 is a deficient number, since it is larger than the sum of its proper divisors (18434295).

129040009 is an equidigital number, since it uses as much as digits as its factorization.

129040009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18434294.

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 129040009 is about 11359.5778530718. The cubic root of 129040009 is about 505.3296661299.

The spelling of 129040009 in words is "one hundred twenty-nine million, forty thousand, nine".