28336668221 has 2 divisors, whose sum is σ = 28336668222. Its totient is φ = 28336668220.

The previous prime is 28336668193. The next prime is 28336668289. The reversal of 28336668221 is 12286663382.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 24689836900 + 3646831321 = 157130^2 + 60389^2 .

It is a cyclic number.

It is not a de Polignac number, because 28336668221 - 2¹⁰ = 28336667197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28336668721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14168334110 + 14168334111.

It is an arithmetic number, because the mean of its divisors is an integer number (14168334111).

Almost surely, 2^28336668221 is an apocalyptic number.

It is an amenable number.

28336668221 is a deficient number, since it is larger than the sum of its proper divisors (1).

28336668221 is an equidigital number, since it uses as much as digits as its factorization.

28336668221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 995328, while the sum is 47.

The spelling of 28336668221 in words is "twenty-eight billion, three hundred thirty-six million, six hundred sixty-eight thousand, two hundred twenty-one".