666511 has 2 divisors, whose sum is σ = 666512. Its totient is φ = 666510.

The previous prime is 666493. The next prime is 666527. The reversal of 666511 is 115666.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 666511 - 2¹³ = 658319 is a prime.

666511 is a lucky number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333255 + 333256.

It is an arithmetic number, because the mean of its divisors is an integer number (333256).

2⁶⁶⁶⁵¹¹ is an apocalyptic number.

666511 is a deficient number, since it is larger than the sum of its proper divisors (1).

666511 is an equidigital number, since it uses as much as digits as its factorization.

666511 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1080, while the sum is 25.

The square root of 666511 is about 816.4012493866. The cubic root of 666511 is about 87.3512465764.

The spelling of 666511 in words is "six hundred sixty-six thousand, five hundred eleven".