668540 has 12 divisors (see below), whose sum is σ = 1403976. Its totient is φ = 267408.

The previous prime is 668539. The next prime is 668543. The reversal of 668540 is 45866.

It is a plaindrome in base 14.

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 (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16694 + ... + 16733.

It is an arithmetic number, because the mean of its divisors is an integer number (116998).

2⁶⁶⁸⁵⁴⁰ is an apocalyptic number.

It is an amenable number.

668540 is an abundant number, since it is smaller than the sum of its proper divisors (735436).

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

668540 is a wasteful number, since it uses less digits than its factorization.

668540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33436 (or 33434 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 29.

The square root of 668540 is about 817.6429538619. The cubic root of 668540 is about 87.4397953202.

The spelling of 668540 in words is "six hundred sixty-eight thousand, five hundred forty".