129378809 has 16 divisors (see below), whose sum is σ = 157977600. Its totient is φ = 103484304.

The previous prime is 129378803. The next prime is 129378811. The reversal of 129378809 is 908873921.

It is not a de Polignac number, because 129378809 - 2²⁰ = 128330233 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129378803) 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 15 ways as a sum of consecutive naturals, for example, 1652 + ... + 16170.

It is an arithmetic number, because the mean of its divisors is an integer number (9873600).

Almost surely, 2^129378809 is an apocalyptic number.

129378809 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

129378809 is a deficient number, since it is larger than the sum of its proper divisors (28598791).

129378809 is a wasteful number, since it uses less digits than its factorization.

129378809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14612.

The product of its (nonzero) digits is 217728, while the sum is 47.

The square root of 129378809 is about 11374.4806035265. The cubic root of 129378809 is about 505.7715344426.

The spelling of 129378809 in words is "one hundred twenty-nine million, three hundred seventy-eight thousand, eight hundred nine".