664605281 has 2 divisors, whose sum is σ = 664605282. Its totient is φ = 664605280.

The previous prime is 664605257. The next prime is 664605289. The reversal of 664605281 is 182506466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 649434256 + 15171025 = 25484^2 + 3895^2 .

It is a cyclic number.

It is not a de Polignac number, because 664605281 - 2¹⁸ = 664343137 is a prime.

It is a super-2 number, since 2×664605281² = 883400359066177922, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (664605289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332302640 + 332302641.

It is an arithmetic number, because the mean of its divisors is an integer number (332302641).

Almost surely, 2^664605281 is an apocalyptic number.

It is an amenable number.

664605281 is a deficient number, since it is larger than the sum of its proper divisors (1).

664605281 is an equidigital number, since it uses as much as digits as its factorization.

664605281 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 69120, while the sum is 38.

The square root of 664605281 is about 25779.9395072991. The cubic root of 664605281 is about 872.6791419857.

The spelling of 664605281 in words is "six hundred sixty-four million, six hundred five thousand, two hundred eighty-one".