66333221 has 2 divisors, whose sum is σ = 66333222. Its totient is φ = 66333220.

The previous prime is 66333209. The next prime is 66333233. The reversal of 66333221 is 12233366.

66333221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a balanced prime because it is at equal distance from previous prime (66333209) and next prime (66333233).

It can be written as a sum of positive squares in only one way, i.e., 64480900 + 1852321 = 8030^2 + 1361^2 .

It is a cyclic number.

It is not a de Polignac number, because 66333221 - 2¹⁰ = 66332197 is a prime.

It is a nialpdrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66333251) 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, 33166610 + 33166611.

It is an arithmetic number, because the mean of its divisors is an integer number (33166611).

Almost surely, 2^66333221 is an apocalyptic number.

It is an amenable number.

66333221 is a deficient number, since it is larger than the sum of its proper divisors (1).

66333221 is an equidigital number, since it uses as much as digits as its factorization.

66333221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3888, while the sum is 26.

The square root of 66333221 is about 8144.5209189982. The cubic root of 66333221 is about 404.8029748365.

Adding to 66333221 its reverse (12233366), we get a palindrome (78566587).

The spelling of 66333221 in words is "sixty-six million, three hundred thirty-three thousand, two hundred twenty-one".