128240869 has 2 divisors, whose sum is σ = 128240870. Its totient is φ = 128240868.

The previous prime is 128240857. The next prime is 128240909. The reversal of 128240869 is 968042821.

It is an a-pointer prime, because the next prime (128240909) can be obtained adding 128240869 to its sum of digits (40).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 83484769 + 44756100 = 9137^2 + 6690^2 .

It is a cyclic number.

It is not a de Polignac number, because 128240869 - 2⁵ = 128240837 is a prime.

It is a super-2 number, since 2×128240869² = 32891440963750322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128240069) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64120434 + 64120435.

It is an arithmetic number, because the mean of its divisors is an integer number (64120435).

Almost surely, 2^128240869 is an apocalyptic number.

It is an amenable number.

128240869 is a deficient number, since it is larger than the sum of its proper divisors (1).

128240869 is an equidigital number, since it uses as much as digits as its factorization.

128240869 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 55296, while the sum is 40.

The square root of 128240869 is about 11324.3485022318. The cubic root of 128240869 is about 504.2843426276.

The spelling of 128240869 in words is "one hundred twenty-eight million, two hundred forty thousand, eight hundred sixty-nine".