667668 has 12 divisors (see below), whose sum is σ = 1557920. Its totient is φ = 222552.

The previous prime is 667657. The next prime is 667673. The reversal of 667668 is 866766.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

667668 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, 27808 + ... + 27831.

2⁶⁶⁷⁶⁶⁸ is an apocalyptic number.

It is an amenable number.

667668 is an abundant number, since it is smaller than the sum of its proper divisors (890252).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

667668 is a wasteful number, since it uses less digits than its factorization.

667668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55646 (or 55644 counting only the distinct ones).

The product of its digits is 72576, while the sum is 39.

The square root of 667668 is about 817.1095397803. The cubic root of 667668 is about 87.4017618560.

The spelling of 667668 in words is "six hundred sixty-seven thousand, six hundred sixty-eight".