666610331 has 4 divisors (see below), whose sum is σ = 667371312. Its totient is φ = 665849352.

The previous prime is 666610297. The next prime is 666610333. The reversal of 666610331 is 133016666.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666610331 is a prime.

It is a super-2 number, since 2×666610331² = 888738666791859122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666610333) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 379175 + ... + 380928.

It is an arithmetic number, because the mean of its divisors is an integer number (166842828).

Almost surely, 2^666610331 is an apocalyptic number.

666610331 is a deficient number, since it is larger than the sum of its proper divisors (760981).

666610331 is an equidigital number, since it uses as much as digits as its factorization.

666610331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 760980.

The product of its (nonzero) digits is 11664, while the sum is 32.

The square root of 666610331 is about 25818.7980161742. The cubic root of 666610331 is about 873.5558571742. Note that the first 3 decimals are identical.

Adding to 666610331 its reverse (133016666), we get a palindrome (799626997).

The spelling of 666610331 in words is "six hundred sixty-six million, six hundred ten thousand, three hundred thirty-one".