128511217 has 2 divisors, whose sum is σ = 128511218. Its totient is φ = 128511216.

The previous prime is 128511203. The next prime is 128511241. The reversal of 128511217 is 712115821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 126540001 + 1971216 = 11249^2 + 1404^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128511217 is a prime.

It is not a weakly prime, because it can be changed into another prime (128511287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64255608 + 64255609.

It is an arithmetic number, because the mean of its divisors is an integer number (64255609).

Almost surely, 2^128511217 is an apocalyptic number.

It is an amenable number.

128511217 is a deficient number, since it is larger than the sum of its proper divisors (1).

128511217 is an equidigital number, since it uses as much as digits as its factorization.

128511217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1120, while the sum is 28.

The square root of 128511217 is about 11336.2787986182. The cubic root of 128511217 is about 504.6384589991.

The spelling of 128511217 in words is "one hundred twenty-eight million, five hundred eleven thousand, two hundred seventeen".