668994 has 16 divisors (see below), whose sum is σ = 1369632. Its totient is φ = 217728.

The previous prime is 668989. The next prime is 668999. The reversal of 668994 is 499866.

It is an interprime number because it is at equal distance from previous prime (668989) and next prime (668999).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (668999) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1039 + ... + 1554.

It is an arithmetic number, because the mean of its divisors is an integer number (85602).

2⁶⁶⁸⁹⁹⁴ is an apocalyptic number.

668994 is an abundant number, since it is smaller than the sum of its proper divisors (700638).

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

668994 is a wasteful number, since it uses less digits than its factorization.

668994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2641.

The product of its digits is 93312, while the sum is 42.

The square root of 668994 is about 817.9205340374. The cubic root of 668994 is about 87.4595840560.

The spelling of 668994 in words is "six hundred sixty-eight thousand, nine hundred ninety-four".