660985 has 8 divisors (see below), whose sum is σ = 854280. Its totient is φ = 488064.

The previous prime is 660983. The next prime is 661009. The reversal of 660985 is 589066.

It can be written as a sum of positive squares in 4 ways, for example, as 95481 + 565504 = 309^2 + 752^2 .

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 660985 - 2¹ = 660983 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 660985.

It is not an unprimeable number, because it can be changed into a prime (660983) 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, 5020 + ... + 5149.

It is an arithmetic number, because the mean of its divisors is an integer number (106785).

2⁶⁶⁰⁹⁸⁵ is an apocalyptic number.

660985 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

660985 is a deficient number, since it is larger than the sum of its proper divisors (193295).

660985 is a wasteful number, since it uses less digits than its factorization.

660985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10187.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 660985 is about 813.0098400389. The cubic root of 660985 is about 87.1091684576.

Subtracting from 660985 its product of nonzero digits (12960), we obtain a square (648025 = 805²).

The spelling of 660985 in words is "six hundred sixty thousand, nine hundred eighty-five".