128444821 has 2 divisors, whose sum is σ = 128444822. Its totient is φ = 128444820.

The previous prime is 128444783. The next prime is 128444839.

128444821 is nontrivially palindromic in base 10.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 111724900 + 16719921 = 10570^2 + 4089^2 .

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 128444821 - 2¹⁷ = 128313749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128444891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64222410 + 64222411.

It is an arithmetic number, because the mean of its divisors is an integer number (64222411).

Almost surely, 2^128444821 is an apocalyptic number.

It is an amenable number.

128444821 is a deficient number, since it is larger than the sum of its proper divisors (1).

128444821 is an equidigital number, since it uses as much as digits as its factorization.

128444821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16384, while the sum is 34.

The square root of 128444821 is about 11333.3499460663. The cubic root of 128444821 is about 504.5515359846.

The spelling of 128444821 in words is "one hundred twenty-eight million, four hundred forty-four thousand, eight hundred twenty-one".