666869 has 4 divisors (see below), whose sum is σ = 762144. Its totient is φ = 571596.

The previous prime is 666857. The next prime is 666871. The reversal of 666869 is 968666.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 666869 - 2¹² = 662773 is a prime.

It is a super-2 number, since 2×666869² = 889428526322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666829) 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 in 3 ways as a sum of consecutive naturals, for example, 47627 + ... + 47640.

It is an arithmetic number, because the mean of its divisors is an integer number (190536).

2⁶⁶⁶⁸⁶⁹ is an apocalyptic number.

It is an amenable number.

666869 is a deficient number, since it is larger than the sum of its proper divisors (95275).

666869 is an equidigital number, since it uses as much as digits as its factorization.

666869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95274.

The product of its digits is 93312, while the sum is 41.

The square root of 666869 is about 816.6204748841. The cubic root of 666869 is about 87.3668833021.

It can be divided in two parts, 66 and 6869, that multiplied together give a palindrome (453354).

The spelling of 666869 in words is "six hundred sixty-six thousand, eight hundred sixty-nine".