664529209 has 2 divisors, whose sum is σ = 664529210. Its totient is φ = 664529208.

The previous prime is 664529149. The next prime is 664529219. The reversal of 664529209 is 902925466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 619263225 + 45265984 = 24885^2 + 6728^2 .

It is a cyclic number.

It is not a de Polignac number, because 664529209 - 2¹³ = 664521017 is a prime.

It is a super-2 number, since 2×664529209² = 883198139228331362, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (664529219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332264604 + 332264605.

It is an arithmetic number, because the mean of its divisors is an integer number (332264605).

Almost surely, 2^664529209 is an apocalyptic number.

It is an amenable number.

664529209 is a deficient number, since it is larger than the sum of its proper divisors (1).

664529209 is an equidigital number, since it uses as much as digits as its factorization.

664529209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 233280, while the sum is 43.

The square root of 664529209 is about 25778.4640543226. The cubic root of 664529209 is about 872.6458445370.

The spelling of 664529209 in words is "six hundred sixty-four million, five hundred twenty-nine thousand, two hundred nine".