666611 has 4 divisors (see below), whose sum is σ = 727224. Its totient is φ = 606000.

The previous prime is 666607. The next prime is 666637. The reversal of 666611 is 116666.

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 666611 - 2² = 666607 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 7 and base 10.

It is a zygodrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (666671) 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, 30290 + ... + 30311.

It is an arithmetic number, because the mean of its divisors is an integer number (181806).

2⁶⁶⁶⁶¹¹ is an apocalyptic number.

666611 is a deficient number, since it is larger than the sum of its proper divisors (60613).

666611 is a wasteful number, since it uses less digits than its factorization.

666611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60612.

The product of its digits is 1296, while the sum is 26.

The square root of 666611 is about 816.4624914838. The cubic root of 666611 is about 87.3556149403.

Subtracting from 666611 its reverse (116666), we obtain a palindrome (549945).

The spelling of 666611 in words is "six hundred sixty-six thousand, six hundred eleven".