129644023 has 4 divisors (see below), whose sum is σ = 137270160. Its totient is φ = 122017888.

The previous prime is 129643993. The next prime is 129644029. The reversal of 129644023 is 320446921.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 129644023 - 2²¹ = 127546871 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 (129644029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3813043 + ... + 3813076.

It is an arithmetic number, because the mean of its divisors is an integer number (34317540).

Almost surely, 2^129644023 is an apocalyptic number.

129644023 is a deficient number, since it is larger than the sum of its proper divisors (7626137).

129644023 is an equidigital number, since it uses as much as digits as its factorization.

129644023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7626136.

The product of its (nonzero) digits is 10368, while the sum is 31.

The square root of 129644023 is about 11386.1329256249. The cubic root of 129644023 is about 506.1168927502.

The spelling of 129644023 in words is "one hundred twenty-nine million, six hundred forty-four thousand, twenty-three".