128821633 has 2 divisors, whose sum is σ = 128821634. Its totient is φ = 128821632.

The previous prime is 128821621. The next prime is 128821639. The reversal of 128821633 is 336128821.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 125260864 + 3560769 = 11192^2 + 1887^2 .

It is a cyclic number.

It is not a de Polignac number, because 128821633 - 2¹³ = 128813441 is a prime.

It is not a weakly prime, because it can be changed into another prime (128821639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64410816 + 64410817.

It is an arithmetic number, because the mean of its divisors is an integer number (64410817).

Almost surely, 2^128821633 is an apocalyptic number.

It is an amenable number.

128821633 is a deficient number, since it is larger than the sum of its proper divisors (1).

128821633 is an equidigital number, since it uses as much as digits as its factorization.

128821633 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13824, while the sum is 34.

The square root of 128821633 is about 11349.9618061031. The cubic root of 128821633 is about 505.0444466321.

The spelling of 128821633 in words is "one hundred twenty-eight million, eight hundred twenty-one thousand, six hundred thirty-three".