668537 has 4 divisors (see below), whose sum is σ = 691620. Its totient is φ = 645456.

The previous prime is 668533. The next prime is 668539. The reversal of 668537 is 735866.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 434281 + 234256 = 659^2 + 484^2 .

It is a cyclic number.

It is not a de Polignac number, because 668537 - 2² = 668533 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 668497 and 668506.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 668537.

It is not an unprimeable number, because it can be changed into a prime (668531) 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, 11498 + ... + 11555.

It is an arithmetic number, because the mean of its divisors is an integer number (172905).

2⁶⁶⁸⁵³⁷ is an apocalyptic number.

It is an amenable number.

668537 is a deficient number, since it is larger than the sum of its proper divisors (23083).

668537 is a wasteful number, since it uses less digits than its factorization.

668537 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23082.

The product of its digits is 30240, while the sum is 35.

The square root of 668537 is about 817.6411193182. The cubic root of 668537 is about 87.4396645278.

The spelling of 668537 in words is "six hundred sixty-eight thousand, five hundred thirty-seven".