660556 has 12 divisors (see below), whose sum is σ = 1244992. Its totient is φ = 304848.

The previous prime is 660547. The next prime is 660557. The reversal of 660556 is 655066.

It is not an unprimeable number, because it can be changed into a prime (660557) by changing a digit.

660556 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6300 + ... + 6403.

2⁶⁶⁰⁵⁵⁶ is an apocalyptic number.

It is an amenable number.

660556 is a deficient number, since it is larger than the sum of its proper divisors (584436).

660556 is a wasteful number, since it uses less digits than its factorization.

660556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12720 (or 12718 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 28.

The square root of 660556 is about 812.7459627707. The cubic root of 660556 is about 87.0903188513.

The spelling of 660556 in words is "six hundred sixty thousand, five hundred fifty-six".