668578 has 4 divisors (see below), whose sum is σ = 1002870. Its totient is φ = 334288.

The previous prime is 668567. The next prime is 668579. The reversal of 668578 is 875866.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 667489 + 1089 = 817^2 + 33^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 668578.

It is not an unprimeable number, because it can be changed into a prime (668579) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 167143 + ... + 167146.

2⁶⁶⁸⁵⁷⁸ is an apocalyptic number.

668578 is a deficient number, since it is larger than the sum of its proper divisors (334292).

668578 is a wasteful number, since it uses less digits than its factorization.

668578 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 334291.

The product of its digits is 80640, while the sum is 40.

The square root of 668578 is about 817.6661910584. Note that the first 3 decimals coincide. The cubic root of 668578 is about 87.4414519895.

The spelling of 668578 in words is "six hundred sixty-eight thousand, five hundred seventy-eight".