668987 has 8 divisors (see below), whose sum is σ = 742512. Its totient is φ = 597600.

The previous prime is 668963. The next prime is 668989. The reversal of 668987 is 789866.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 668987 - 2¹⁰ = 667963 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 668987.

It is not an unprimeable number, because it can be changed into a prime (668989) 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 7 ways as a sum of consecutive naturals, for example, 173 + ... + 1169.

It is an arithmetic number, because the mean of its divisors is an integer number (92814).

2⁶⁶⁸⁹⁸⁷ is an apocalyptic number.

668987 is a deficient number, since it is larger than the sum of its proper divisors (73525).

668987 is a wasteful number, since it uses less digits than its factorization.

668987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1069.

The product of its digits is 145152, while the sum is 44.

The square root of 668987 is about 817.9162548819. The cubic root of 668987 is about 87.4592790113.

It can be divided in two parts, 6689 and 87, that added together give a palindrome (6776).

The spelling of 668987 in words is "six hundred sixty-eight thousand, nine hundred eighty-seven".