128070821 has 2 divisors, whose sum is σ = 128070822. Its totient is φ = 128070820.

The previous prime is 128070799. The next prime is 128070841.

128070821 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., 105165025 + 22905796 = 10255^2 + 4786^2 .

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 128070821 - 2²² = 123876517 is a prime.

It is a super-2 number, since 2×128070821² = 32804270383228082, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128070841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64035410 + 64035411.

It is an arithmetic number, because the mean of its divisors is an integer number (64035411).

Almost surely, 2^128070821 is an apocalyptic number.

It is an amenable number.

128070821 is a deficient number, since it is larger than the sum of its proper divisors (1).

128070821 is an equidigital number, since it uses as much as digits as its factorization.

128070821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1792, while the sum is 29.

The square root of 128070821 is about 11316.8379417574. The cubic root of 128070821 is about 504.0613495593.

The spelling of 128070821 in words is "one hundred twenty-eight million, seventy thousand, eight hundred twenty-one".