128323717729 has 3 divisors (see below), whose sum is σ = 128324075953. Its totient is φ = 128323359506.

The previous prime is 128323717721. The next prime is 128323717733. The reversal of 128323717729 is 927717323821.

The square root of 128323717729 is 358223.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 927717323821 = 4637 ⋅200068433.

It is not a de Polignac number, because 128323717729 - 2³ = 128323717721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128323717721) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 179112 + ... + 537334.

Almost surely, 2^128323717729 is an apocalyptic number.

128323717729 is the 358223-rd square number.

128323717729 is the 179112-nd centered octagonal number.

It is an amenable number.

128323717729 is a deficient number, since it is larger than the sum of its proper divisors (358224).

128323717729 is an frugal number, since it uses more digits than its factorization.

128323717729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 716446 (or 358223 counting only the distinct ones).

The product of its digits is 1778112, while the sum is 52.

The spelling of 128323717729 in words is "one hundred twenty-eight billion, three hundred twenty-three million, seven hundred seventeen thousand, seven hundred twenty-nine".