668655 has 40 divisors (see below), whose sum is σ = 1300992. Its totient is φ = 326592.

The previous prime is 668623. The next prime is 668671. The reversal of 668655 is 556866.

It is not a de Polignac number, because 668655 - 2⁵ = 668623 is a prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 668655.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 5202 + ... + 5328.

2⁶⁶⁸⁶⁵⁵ is an apocalyptic number.

668655 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

668655 is a deficient number, since it is larger than the sum of its proper divisors (632337).

668655 is a wasteful number, since it uses less digits than its factorization.

668655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157 (or 148 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The square root of 668655 is about 817.7132749320. The cubic root of 668655 is about 87.4448087324. Note that the first 3 decimals are identical.

The spelling of 668655 in words is "six hundred sixty-eight thousand, six hundred fifty-five".