129720778423 has 4 divisors (see below), whose sum is σ = 129812845680. Its totient is φ = 129628711168.

The previous prime is 129720778403. The next prime is 129720778433. The reversal of 129720778423 is 324877027921.

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 129720778423 - 2¹⁷ = 129720647351 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 (129720778403) 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, 46031515 + ... + 46034332.

It is an arithmetic number, because the mean of its divisors is an integer number (32453211420).

Almost surely, 2^129720778423 is an apocalyptic number.

129720778423 is a deficient number, since it is larger than the sum of its proper divisors (92067257).

129720778423 is an equidigital number, since it uses as much as digits as its factorization.

129720778423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92067256.

The product of its (nonzero) digits is 2370816, while the sum is 52.

The spelling of 129720778423 in words is "one hundred twenty-nine billion, seven hundred twenty million, seven hundred seventy-eight thousand, four hundred twenty-three".