128381321 has 2 divisors, whose sum is σ = 128381322. Its totient is φ = 128381320.

The previous prime is 128381303. The next prime is 128381327. The reversal of 128381321 is 123183821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 93334921 + 35046400 = 9661^2 + 5920^2 .

It is a cyclic number.

It is not a de Polignac number, because 128381321 - 2¹⁴ = 128364937 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (128381327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64190660 + 64190661.

It is an arithmetic number, because the mean of its divisors is an integer number (64190661).

Almost surely, 2^128381321 is an apocalyptic number.

It is an amenable number.

128381321 is a deficient number, since it is larger than the sum of its proper divisors (1).

128381321 is an equidigital number, since it uses as much as digits as its factorization.

128381321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2304, while the sum is 29.

The square root of 128381321 is about 11330.5481332546. The cubic root of 128381321 is about 504.4683762706.

The spelling of 128381321 in words is "one hundred twenty-eight million, three hundred eighty-one thousand, three hundred twenty-one".