668605 has 12 divisors (see below), whose sum is σ = 933660. Its totient is φ = 458304.

The previous prime is 668599. The next prime is 668609. The reversal of 668605 is 506866.

It can be written as a sum of positive squares in 2 ways, for example, as 480249 + 188356 = 693^2 + 434^2 .

It is not a de Polignac number, because 668605 - 2⁹ = 668093 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668609) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1120 + ... + 1609.

It is an arithmetic number, because the mean of its divisors is an integer number (77805).

2⁶⁶⁸⁶⁰⁵ is an apocalyptic number.

It is an amenable number.

668605 is a deficient number, since it is larger than the sum of its proper divisors (265055).

668605 is a wasteful number, since it uses less digits than its factorization.

668605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2748 (or 2741 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 668605 is about 817.6827012968. The cubic root of 668605 is about 87.4426290586.

The spelling of 668605 in words is "six hundred sixty-eight thousand, six hundred five".