128669 has 2 divisors, whose sum is σ = 128670. Its totient is φ = 128668.

The previous prime is 128663. The next prime is 128677. The reversal of 128669 is 966821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 68644 + 60025 = 262^2 + 245^2 .

It is a cyclic number.

It is not a de Polignac number, because 128669 - 2⁸ = 128413 is a prime.

It is a super-2 number, since 2×128669² = 33111423122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a nialpdrome in base 11.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64334 + 64335.

It is an arithmetic number, because the mean of its divisors is an integer number (64335).

2¹²⁸⁶⁶⁹ is an apocalyptic number.

It is an amenable number.

128669 is a deficient number, since it is larger than the sum of its proper divisors (1).

128669 is an equidigital number, since it uses as much as digits as its factorization.

128669 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5184, while the sum is 32.

The square root of 128669 is about 358.7046138538. The cubic root of 128669 is about 50.4844902212.

It can be divided in two parts, 128 and 669, that added together give a palindrome (797).

The spelling of 128669 in words is "one hundred twenty-eight thousand, six hundred sixty-nine".