666635 has 4 divisors (see below), whose sum is σ = 799968. Its totient is φ = 533304.

The previous prime is 666607. The next prime is 666637. The reversal of 666635 is 536666.

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

It is a cyclic number.

It is not a de Polignac number, because 666635 - 2¹² = 662539 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 666635.

It is not an unprimeable number, because it can be changed into a prime (666637) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66659 + ... + 66668.

It is an arithmetic number, because the mean of its divisors is an integer number (199992).

2⁶⁶⁶⁶³⁵ is an apocalyptic number.

666635 is a deficient number, since it is larger than the sum of its proper divisors (133333).

666635 is a wasteful number, since it uses less digits than its factorization.

666635 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133332.

The product of its digits is 19440, while the sum is 32.

The square root of 666635 is about 816.4771889036. The cubic root of 666635 is about 87.3566632827.

The spelling of 666635 in words is "six hundred sixty-six thousand, six hundred thirty-five".