660865 has 4 divisors (see below), whose sum is σ = 793044. Its totient is φ = 528688.

The previous prime is 660853. The next prime is 660887. The reversal of 660865 is 568066.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 207936 + 452929 = 456^2 + 673^2 .

It is a cyclic number.

It is not a de Polignac number, because 660865 - 2⁵ = 660833 is a prime.

It is a Duffinian number.

It is an unprimeable 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, 66082 + ... + 66091.

It is an arithmetic number, because the mean of its divisors is an integer number (198261).

2⁶⁶⁰⁸⁶⁵ is an apocalyptic number.

It is an amenable number.

660865 is a deficient number, since it is larger than the sum of its proper divisors (132179).

660865 is a wasteful number, since it uses less digits than its factorization.

660865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132178.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 660865 is about 812.9360368442. The cubic root of 660865 is about 87.1038966622.

The spelling of 660865 in words is "six hundred sixty thousand, eight hundred sixty-five".