129439819 has 4 divisors (see below), whose sum is σ = 137053944. Its totient is φ = 121825696.

The previous prime is 129439781. The next prime is 129439823. The reversal of 129439819 is 918934921.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 918934921 = 7933 ⋅115837.

It is a cyclic number.

It is not a de Polignac number, because 129439819 - 2²³ = 121051211 is a prime.

It is a super-2 number, since 2×129439819² = 33509333485505522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129439859) 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, 3807037 + ... + 3807070.

It is an arithmetic number, because the mean of its divisors is an integer number (34263486).

Almost surely, 2^129439819 is an apocalyptic number.

129439819 is a deficient number, since it is larger than the sum of its proper divisors (7614125).

129439819 is an equidigital number, since it uses as much as digits as its factorization.

129439819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7614124.

The product of its digits is 139968, while the sum is 46.

The square root of 129439819 is about 11377.1621681331. The cubic root of 129439819 is about 505.8510226588.

The spelling of 129439819 in words is "one hundred twenty-nine million, four hundred thirty-nine thousand, eight hundred nineteen".