28896221 has 2 divisors, whose sum is σ = 28896222. Its totient is φ = 28896220.

The previous prime is 28896191. The next prime is 28896233. The reversal of 28896221 is 12269882.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17131321 + 11764900 = 4139^2 + 3430^2 .

It is a cyclic number.

It is not a de Polignac number, because 28896221 - 2¹⁰ = 28895197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28896271) 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, 14448110 + 14448111.

It is an arithmetic number, because the mean of its divisors is an integer number (14448111).

Almost surely, 2^28896221 is an apocalyptic number.

It is an amenable number.

28896221 is a deficient number, since it is larger than the sum of its proper divisors (1).

28896221 is an equidigital number, since it uses as much as digits as its factorization.

28896221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27648, while the sum is 38.

The square root of 28896221 is about 5375.5205329345. The cubic root of 28896221 is about 306.8647595108.

The spelling of 28896221 in words is "twenty-eight million, eight hundred ninety-six thousand, two hundred twenty-one".