66104221 has 2 divisors, whose sum is σ = 66104222. Its totient is φ = 66104220.

The previous prime is 66104219. The next prime is 66104251. The reversal of 66104221 is 12240166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 63824121 + 2280100 = 7989^2 + 1510^2 .

It is a cyclic number.

It is not a de Polignac number, because 66104221 - 2¹ = 66104219 is a prime.

Together with 66104219, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 66104192 and 66104201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66104251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33052110 + 33052111.

It is an arithmetic number, because the mean of its divisors is an integer number (33052111).

Almost surely, 2^66104221 is an apocalyptic number.

It is an amenable number.

66104221 is a deficient number, since it is larger than the sum of its proper divisors (1).

66104221 is an equidigital number, since it uses as much as digits as its factorization.

66104221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 66104221 is about 8130.4502335357. The cubic root of 66104221 is about 404.3366084124.

Adding to 66104221 its reverse (12240166), we get a palindrome (78344387).

The spelling of 66104221 in words is "sixty-six million, one hundred four thousand, two hundred twenty-one".