129409391 has 4 divisors (see below), whose sum is σ = 129866952. Its totient is φ = 128951832.

The previous prime is 129409373. The next prime is 129409393. The reversal of 129409391 is 193904921.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 193904921 = 7 ⋅27700703.

It is a cyclic number.

It is not a de Polignac number, because 129409391 - 2²² = 125215087 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129409393) 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, 228356 + ... + 228921.

It is an arithmetic number, because the mean of its divisors is an integer number (32466738).

Almost surely, 2^129409391 is an apocalyptic number.

129409391 is a deficient number, since it is larger than the sum of its proper divisors (457561).

129409391 is an equidigital number, since it uses as much as digits as its factorization.

129409391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 457560.

The product of its (nonzero) digits is 17496, while the sum is 38.

The square root of 129409391 is about 11375.8248492142. The cubic root of 129409391 is about 505.8113819947.

The spelling of 129409391 in words is "one hundred twenty-nine million, four hundred nine thousand, three hundred ninety-one".