666617 has 4 divisors (see below), whose sum is σ = 761856. Its totient is φ = 571380.

The previous prime is 666607. The next prime is 666637. The reversal of 666617 is 716666.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666617 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 7.

It is not an unprimeable number, because it can be changed into a prime (666607) 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, 47609 + ... + 47622.

It is an arithmetic number, because the mean of its divisors is an integer number (190464).

2⁶⁶⁶⁶¹⁷ is an apocalyptic number.

It is an amenable number.

666617 is a deficient number, since it is larger than the sum of its proper divisors (95239).

666617 is an equidigital number, since it uses as much as digits as its factorization.

666617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95238.

The product of its digits is 9072, while the sum is 32.

The square root of 666617 is about 816.4661658636. The cubic root of 666617 is about 87.3558770283.

The spelling of 666617 in words is "six hundred sixty-six thousand, six hundred seventeen".