28182221 has 2 divisors, whose sum is σ = 28182222. Its totient is φ = 28182220.

The previous prime is 28182191. The next prime is 28182233. The reversal of 28182221 is 12228182.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27678121 + 504100 = 5261^2 + 710^2 .

It is a cyclic number.

It is not a de Polignac number, because 28182221 - 2²² = 23987917 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28182421) 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, 14091110 + 14091111.

It is an arithmetic number, because the mean of its divisors is an integer number (14091111).

Almost surely, 2^28182221 is an apocalyptic number.

It is an amenable number.

28182221 is a deficient number, since it is larger than the sum of its proper divisors (1).

28182221 is an equidigital number, since it uses as much as digits as its factorization.

28182221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1024, while the sum is 26.

The square root of 28182221 is about 5308.6929653164. The cubic root of 28182221 is about 304.3161998805.

The spelling of 28182221 in words is "twenty-eight million, one hundred eighty-two thousand, two hundred twenty-one".