128729017 has 4 divisors (see below), whose sum is σ = 129005136. Its totient is φ = 128452900.

The previous prime is 128729011. The next prime is 128729021. The reversal of 128729017 is 710927821.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128729017 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128729011) 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, 137359 + ... + 138292.

It is an arithmetic number, because the mean of its divisors is an integer number (32251284).

Almost surely, 2^128729017 is an apocalyptic number.

It is an amenable number.

128729017 is a deficient number, since it is larger than the sum of its proper divisors (276119).

128729017 is an equidigital number, since it uses as much as digits as its factorization.

128729017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276118.

The product of its (nonzero) digits is 14112, while the sum is 37.

The square root of 128729017 is about 11345.8810587808. The cubic root of 128729017 is about 504.9233841224.

The spelling of 128729017 in words is "one hundred twenty-eight million, seven hundred twenty-nine thousand, seventeen".