128671217 has 2 divisors, whose sum is σ = 128671218. Its totient is φ = 128671216.

The previous prime is 128671189. The next prime is 128671229. The reversal of 128671217 is 712176821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 96510976 + 32160241 = 9824^2 + 5671^2 .

It is an emirp because it is prime and its reverse (712176821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 128671217 - 2⁸ = 128670961 is a prime.

It is a super-2 number, since 2×128671217² = 33112564168522178, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (128671247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64335608 + 64335609.

It is an arithmetic number, because the mean of its divisors is an integer number (64335609).

Almost surely, 2^128671217 is an apocalyptic number.

It is an amenable number.

128671217 is a deficient number, since it is larger than the sum of its proper divisors (1).

128671217 is an equidigital number, since it uses as much as digits as its factorization.

128671217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9408, while the sum is 35.

The square root of 128671217 is about 11343.3335929082. Note that the first 3 decimals coincide. The cubic root of 128671217 is about 504.8478017313.

The spelling of 128671217 in words is "one hundred twenty-eight million, six hundred seventy-one thousand, two hundred seventeen".