66032221 has 2 divisors, whose sum is σ = 66032222. Its totient is φ = 66032220.

The previous prime is 66032191. The next prime is 66032231. The reversal of 66032221 is 12223066.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 39879225 + 26152996 = 6315^2 + 5114^2 .

It is a cyclic number.

It is not a de Polignac number, because 66032221 - 2⁷ = 66032093 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 66032192 and 66032201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66032231) 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, 33016110 + 33016111.

It is an arithmetic number, because the mean of its divisors is an integer number (33016111).

Almost surely, 2^66032221 is an apocalyptic number.

It is an amenable number.

66032221 is a deficient number, since it is larger than the sum of its proper divisors (1).

66032221 is an equidigital number, since it uses as much as digits as its factorization.

66032221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 22.

The square root of 66032221 is about 8126.0212281288. The cubic root of 66032221 is about 404.1897554009.

Adding to 66032221 its reverse (12223066), we get a palindrome (78255287).

The spelling of 66032221 in words is "sixty-six million, thirty-two thousand, two hundred twenty-one".