664247219 has 2 divisors, whose sum is σ = 664247220. Its totient is φ = 664247218.

The previous prime is 664247209. The next prime is 664247263. The reversal of 664247219 is 912742466.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 664247219 - 2⁸ = 664246963 is a prime.

It is a super-2 number, since 2×664247219² = 882448735898467922, which contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (664247209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332123609 + 332123610.

It is an arithmetic number, because the mean of its divisors is an integer number (332123610).

Almost surely, 2^664247219 is an apocalyptic number.

664247219 is a deficient number, since it is larger than the sum of its proper divisors (1).

664247219 is an equidigital number, since it uses as much as digits as its factorization.

664247219 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 41.

The square root of 664247219 is about 25772.9939859536. The cubic root of 664247219 is about 872.5223926186.

It can be divided in two parts, 664247 and 219, that added together give a palindrome (664466).

The spelling of 664247219 in words is "six hundred sixty-four million, two hundred forty-seven thousand, two hundred nineteen".