128969 has 2 divisors, whose sum is σ = 128970. Its totient is φ = 128968.

The previous prime is 128959. The next prime is 128971. The reversal of 128969 is 969821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 102400 + 26569 = 320^2 + 163^2 .

It is an emirp because it is prime and its reverse (969821) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128969 is a prime.

It is a super-2 number, since 2×128969² = 33266005922, which contains 22 as substring.

Together with 128971, it forms a pair of twin primes.

It is a Chen prime.

It is an Ulam number.

It is not a weakly prime, because it can be changed into another prime (128939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64484 + 64485.

It is an arithmetic number, because the mean of its divisors is an integer number (64485).

2¹²⁸⁹⁶⁹ is an apocalyptic number.

It is an amenable number.

128969 is a deficient number, since it is larger than the sum of its proper divisors (1).

128969 is an equidigital number, since it uses as much as digits as its factorization.

128969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 35.

The square root of 128969 is about 359.1225417598. The cubic root of 128969 is about 50.5236957058.

The spelling of 128969 in words is "one hundred twenty-eight thousand, nine hundred sixty-nine".