666529 has 2 divisors, whose sum is σ = 666530. Its totient is φ = 666528.

The previous prime is 666527. The next prime is 666541. The reversal of 666529 is 925666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 664225 + 2304 = 815^2 + 48^2 .

It is a cyclic number.

It is not a de Polignac number, because 666529 - 2¹ = 666527 is a prime.

Together with 666527, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 666494 and 666503.

It is not a weakly prime, because it can be changed into another prime (666527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333264 + 333265.

It is an arithmetic number, because the mean of its divisors is an integer number (333265).

2⁶⁶⁶⁵²⁹ is an apocalyptic number.

It is an amenable number.

666529 is a deficient number, since it is larger than the sum of its proper divisors (1).

666529 is an equidigital number, since it uses as much as digits as its factorization.

666529 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 19440, while the sum is 34.

The square root of 666529 is about 816.4122733031. The cubic root of 666529 is about 87.3520329141.

The spelling of 666529 in words is "six hundred sixty-six thousand, five hundred twenty-nine".