128355209 has 2 divisors, whose sum is σ = 128355210. Its totient is φ = 128355208.

The previous prime is 128355197. The next prime is 128355277. The reversal of 128355209 is 902553821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 91145209 + 37210000 = 9547^2 + 6100^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128355209 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (128355509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64177604 + 64177605.

It is an arithmetic number, because the mean of its divisors is an integer number (64177605).

Almost surely, 2^128355209 is an apocalyptic number.

It is an amenable number.

128355209 is a deficient number, since it is larger than the sum of its proper divisors (1).

128355209 is an equidigital number, since it uses as much as digits as its factorization.

128355209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21600, while the sum is 35.

The square root of 128355209 is about 11329.3957914798. The cubic root of 128355209 is about 504.4341719919.

The spelling of 128355209 in words is "one hundred twenty-eight million, three hundred fifty-five thousand, two hundred nine".