66849221 has 2 divisors, whose sum is σ = 66849222. Its totient is φ = 66849220.

The previous prime is 66849197. The next prime is 66849227. The reversal of 66849221 is 12294866.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65788321 + 1060900 = 8111^2 + 1030^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66849221 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 (66849227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33424610 + 33424611.

It is an arithmetic number, because the mean of its divisors is an integer number (33424611).

Almost surely, 2^66849221 is an apocalyptic number.

It is an amenable number.

66849221 is a deficient number, since it is larger than the sum of its proper divisors (1).

66849221 is an equidigital number, since it uses as much as digits as its factorization.

66849221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 41472, while the sum is 38.

The square root of 66849221 is about 8176.1372909217. The cubic root of 66849221 is about 405.8499065014.

The spelling of 66849221 in words is "sixty-six million, eight hundred forty-nine thousand, two hundred twenty-one".