128939317 has 4 divisors (see below), whose sum is σ = 138857740. Its totient is φ = 119020896.

The previous prime is 128939309. The next prime is 128939329. The reversal of 128939317 is 713939821.

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

It can be written as a sum of positive squares in 2 ways, for example, as 8071281 + 120868036 = 2841^2 + 10994^2 .

It is a cyclic number.

It is not a de Polignac number, because 128939317 - 2³ = 128939309 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 (128939617) 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, 4959192 + ... + 4959217.

It is an arithmetic number, because the mean of its divisors is an integer number (34714435).

Almost surely, 2^128939317 is an apocalyptic number.

It is an amenable number.

128939317 is a deficient number, since it is larger than the sum of its proper divisors (9918423).

128939317 is an equidigital number, since it uses as much as digits as its factorization.

128939317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9918422.

The product of its digits is 81648, while the sum is 43.

The square root of 128939317 is about 11355.1449572430. The cubic root of 128939317 is about 505.1981929645.

The spelling of 128939317 in words is "one hundred twenty-eight million, nine hundred thirty-nine thousand, three hundred seventeen".