668481 has 16 divisors (see below), whose sum is σ = 995328. Its totient is φ = 395600.

The previous prime is 668471. The next prime is 668509. The reversal of 668481 is 184866.

It is a cyclic number.

It is not a de Polignac number, because 668481 - 2⁶ = 668417 is a prime.

It is a super-2 number, since 2×668481² = 893733694722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is an Ulam number.

It is a Curzon number.

It is a plaindrome in base 14.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 668481.

It is not an unprimeable number, because it can be changed into a prime (668471) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1336 + ... + 1766.

It is an arithmetic number, because the mean of its divisors is an integer number (62208).

2⁶⁶⁸⁴⁸¹ is an apocalyptic number.

It is an amenable number.

668481 is a deficient number, since it is larger than the sum of its proper divisors (326847).

668481 is a wasteful number, since it uses less digits than its factorization.

668481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 492.

The product of its digits is 9216, while the sum is 33.

The square root of 668481 is about 817.6068737480. The cubic root of 668481 is about 87.4372229985.

The spelling of 668481 in words is "six hundred sixty-eight thousand, four hundred eighty-one".