666769 has 2 divisors, whose sum is σ = 666770. Its totient is φ = 666768.

The previous prime is 666751. The next prime is 666773. The reversal of 666769 is 967666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 497025 + 169744 = 705^2 + 412^2 .

It is a cyclic number.

It is not a de Polignac number, because 666769 - 2⁵ = 666737 is a prime.

It is a super-2 number, since 2×666769² = 889161798722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (666749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333384 + 333385.

It is an arithmetic number, because the mean of its divisors is an integer number (333385).

2⁶⁶⁶⁷⁶⁹ is an apocalyptic number.

It is an amenable number.

666769 is a deficient number, since it is larger than the sum of its proper divisors (1).

666769 is an equidigital number, since it uses as much as digits as its factorization.

666769 is an evil number, because the sum of its binary digits is even.

The product of its digits is 81648, while the sum is 40.

The square root of 666769 is about 816.5592446357. The cubic root of 666769 is about 87.3625160650.

The spelling of 666769 in words is "six hundred sixty-six thousand, seven hundred sixty-nine".