129372817 has 4 divisors (see below), whose sum is σ = 147854656. Its totient is φ = 110890980.

The previous prime is 129372797. The next prime is 129372821. The reversal of 129372817 is 718273921.

It is a happy number.

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, and also an emirpimes, since its reverse is a distinct semiprime: 718273921 = 109 ⋅6589669.

It is a cyclic number.

It is not a de Polignac number, because 129372817 - 2⁷ = 129372689 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 129372817.

It is not an unprimeable number, because it can be changed into a prime (129370817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9240909 + ... + 9240922.

It is an arithmetic number, because the mean of its divisors is an integer number (36963664).

Almost surely, 2^129372817 is an apocalyptic number.

It is an amenable number.

129372817 is a deficient number, since it is larger than the sum of its proper divisors (18481839).

129372817 is an equidigital number, since it uses as much as digits as its factorization.

129372817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18481838.

The product of its digits is 42336, while the sum is 40.

The square root of 129372817 is about 11374.2172038343. The cubic root of 129372817 is about 505.7637262865.

The spelling of 129372817 in words is "one hundred twenty-nine million, three hundred seventy-two thousand, eight hundred seventeen".