1668 has 12 divisors (see below), whose sum is σ = 3920. Its totient is φ = 552.

The previous prime is 1667. The next prime is 1669. The reversal of 1668 is 8661.

It is an interprime number because it is at equal distance from previous prime (1667) and next prime (1669).

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

Its product of digits (288) is a multiple of the sum of its prime divisors (144).

It is a plaindrome in base 10.

It is a nialpdrome in base 12, base 14 and base 15.

It is not an unprimeable number, because it can be changed into a prime (1663) 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, 58 + ... + 81.

It is an amenable number.

1668 is an abundant number, since it is smaller than the sum of its proper divisors (2252).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1960).

1668 is a wasteful number, since it uses less digits than its factorization.

1668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146 (or 144 counting only the distinct ones).

The product of its digits is 288, while the sum is 21.

The square root of 1668 is about 40.8411557133. The cubic root of 1668 is about 11.8594718552.

The spelling of 1668 in words is "one thousand, six hundred sixty-eight".