666601 has 8 divisors (see below), whose sum is σ = 733824. Its totient is φ = 601680.

The previous prime is 666599. The next prime is 666607. The reversal of 666601 is 106666.

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 666601 - 2¹ = 666599 is a prime.

It is not an unprimeable number, because it can be changed into a prime (666607) 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, 66 + ... + 1156.

It is an arithmetic number, because the mean of its divisors is an integer number (91728).

2⁶⁶⁶⁶⁰¹ is an apocalyptic number.

It is an amenable number.

666601 is a deficient number, since it is larger than the sum of its proper divisors (67223).

666601 is a wasteful number, since it uses less digits than its factorization.

666601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1151.

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 666601 is about 816.4563674808. The cubic root of 666601 is about 87.3551781236.

The spelling of 666601 in words is "six hundred sixty-six thousand, six hundred one".