128270921 has 2 divisors, whose sum is σ = 128270922. Its totient is φ = 128270920.

The previous prime is 128270917. The next prime is 128270959. The reversal of 128270921 is 129072821.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78765625 + 49505296 = 8875^2 + 7036^2 .

It is an emirp because it is prime and its reverse (129072821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 128270921 - 2² = 128270917 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (128270911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64135460 + 64135461.

It is an arithmetic number, because the mean of its divisors is an integer number (64135461).

Almost surely, 2^128270921 is an apocalyptic number.

It is an amenable number.

128270921 is a deficient number, since it is larger than the sum of its proper divisors (1).

128270921 is an equidigital number, since it uses as much as digits as its factorization.

128270921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4032, while the sum is 32.

The square root of 128270921 is about 11325.6752999545. The cubic root of 128270921 is about 504.3237309276.

The spelling of 128270921 in words is "one hundred twenty-eight million, two hundred seventy thousand, nine hundred twenty-one".