660665 has 8 divisors (see below), whose sum is σ = 797640.
Its totient is φ = 525312.
The previous prime is 660661. The next prime is 660683. The reversal of 660665 is 566066.
It can be written as a sum of positive squares in 4 ways, for example, as 426409 + 234256 = 653^2 + 484^2
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 660665 - 22 = 660661 is a prime.
It is not an unprimeable number, because it can be changed into a prime (660661) by changing a digit.
It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 857 + ... + 1433.
It is an arithmetic number, because the mean of its divisors is an integer number (99705).
2660665 is an apocalyptic number.
It is an amenable number.
660665 is a deficient number, since it is larger than the sum of its proper divisors (136975).
660665 is a wasteful number, since it uses less digits than its factorization.
660665 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 811.
The product of its (nonzero) digits is 6480, while the sum is 29.
The square root of 660665 is about 812.8130166281.
The cubic root of 660665 is about 87.0951089184.
The spelling of 660665 in words is "six hundred sixty thousand, six hundred sixty-five".