128499221 has 2 divisors, whose sum is σ = 128499222. Its totient is φ = 128499220.

The previous prime is 128499167. The next prime is 128499281. The reversal of 128499221 is 122994821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 128368900 + 130321 = 11330^2 + 361^2 .

It is a cyclic number.

It is not a de Polignac number, because 128499221 - 2⁶ = 128499157 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128499281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64249610 + 64249611.

It is an arithmetic number, because the mean of its divisors is an integer number (64249611).

Almost surely, 2^128499221 is an apocalyptic number.

It is an amenable number.

128499221 is a deficient number, since it is larger than the sum of its proper divisors (1).

128499221 is an equidigital number, since it uses as much as digits as its factorization.

128499221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20736, while the sum is 38.

The square root of 128499221 is about 11335.7496884855. The cubic root of 128499221 is about 504.6227565272.

The spelling of 128499221 in words is "one hundred twenty-eight million, four hundred ninety-nine thousand, two hundred twenty-one".