666659 has 8 divisors (see below), whose sum is σ = 768768. Its totient is φ = 566280.

The previous prime is 666649. The next prime is 666667. The reversal of 666659 is 956666.

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 666659 - 2⁴ = 666643 is a prime.

It is a nialpdrome in base 7.

It is not an unprimeable number, because it can be changed into a prime (666649) 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, 554 + ... + 1280.

It is an arithmetic number, because the mean of its divisors is an integer number (96096).

2⁶⁶⁶⁶⁵⁹ is an apocalyptic number.

666659 is a deficient number, since it is larger than the sum of its proper divisors (102109).

666659 is a wasteful number, since it uses less digits than its factorization.

666659 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 865.

The product of its digits is 58320, while the sum is 38.

The square root of 666659 is about 816.4918860589. The cubic root of 666659 is about 87.3577115998.

The spelling of 666659 in words is "six hundred sixty-six thousand, six hundred fifty-nine".