667988 has 12 divisors (see below), whose sum is σ = 1206912. Its totient is φ = 323160.

The previous prime is 667987. The next prime is 667991. The reversal of 667988 is 889766.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667987) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2570 + ... + 2817.

It is an arithmetic number, because the mean of its divisors is an integer number (100576).

2⁶⁶⁷⁹⁸⁸ is an apocalyptic number.

It is an amenable number.

667988 is a deficient number, since it is larger than the sum of its proper divisors (538924).

667988 is a wasteful number, since it uses less digits than its factorization.

667988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5422 (or 5420 counting only the distinct ones).

The product of its digits is 145152, while the sum is 44.

The square root of 667988 is about 817.3053285034. The cubic root of 667988 is about 87.4157229349.

The spelling of 667988 in words is "six hundred sixty-seven thousand, nine hundred eighty-eight".