668544 has 32 divisors (see below), whose sum is σ = 1776840. Its totient is φ = 222720.

The previous prime is 668543. The next prime is 668567. The reversal of 668544 is 445866.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 487 + ... + 1254.

2⁶⁶⁸⁵⁴⁴ is an apocalyptic number.

668544 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

668544 is an abundant number, since it is smaller than the sum of its proper divisors (1108296).

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

668544 is a wasteful number, since it uses less digits than its factorization.

668544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1758 (or 1746 counting only the distinct ones).

The product of its digits is 23040, while the sum is 33.

The square root of 668544 is about 817.6453999137. The cubic root of 668544 is about 87.4399697094.

The spelling of 668544 in words is "six hundred sixty-eight thousand, five hundred forty-four".