689666 has 8 divisors (see below), whose sum is σ = 1051644. Its totient is φ = 339120.

The previous prime is 689641. The next prime is 689693. The reversal of 689666 is 666986.

It can be written as a sum of positive squares in 2 ways, for example, as 674041 + 15625 = 821^2 + 125^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 689666.

It is an unprimeable number.

689666 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2705 + ... + 2948.

2⁶⁸⁹⁶⁶⁶ is an apocalyptic number.

689666 is a deficient number, since it is larger than the sum of its proper divisors (361978).

689666 is a wasteful number, since it uses less digits than its factorization.

689666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5716.

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

The square root of 689666 is about 830.4613175820. The cubic root of 689666 is about 88.3512989051.

The spelling of 689666 in words is "six hundred eighty-nine thousand, six hundred sixty-six".