668817 has 20 divisors (see below), whose sum is σ = 1045440. Its totient is φ = 425304.

The previous prime is 668813. The next prime is 668821. The reversal of 668817 is 718866.

It is an interprime number because it is at equal distance from previous prime (668813) and next prime (668821).

It is not a de Polignac number, because 668817 - 2² = 668813 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 668817.

It is not an unprimeable number, because it can be changed into a prime (668813) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1684 + ... + 2042.

It is an arithmetic number, because the mean of its divisors is an integer number (52272).

2⁶⁶⁸⁸¹⁷ is an apocalyptic number.

It is an amenable number.

668817 is a deficient number, since it is larger than the sum of its proper divisors (376623).

668817 is a wasteful number, since it uses less digits than its factorization.

668817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 394 (or 385 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 668817 is about 817.8123256591. The cubic root of 668817 is about 87.4518701294.

It can be divided in two parts, 668 and 817, that added together give a triangular number (1485 = T₅₄).

The spelling of 668817 in words is "six hundred sixty-eight thousand, eight hundred seventeen".