666331 has 4 divisors (see below), whose sum is σ = 668032. Its totient is φ = 664632.

The previous prime is 666329. The next prime is 666353. The reversal of 666331 is 133666.

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 666331 - 2¹ = 666329 is a prime.

It is a super-2 number, since 2×666331² = 887994003122, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 666296 and 666305.

It is not an unprimeable number, because it can be changed into a prime (666301) 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 3 ways as a sum of consecutive naturals, for example, 70 + ... + 1156.

It is an arithmetic number, because the mean of its divisors is an integer number (167008).

2⁶⁶⁶³³¹ is an apocalyptic number.

666331 is a deficient number, since it is larger than the sum of its proper divisors (1701).

666331 is a wasteful number, since it uses less digits than its factorization.

666331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1700.

The product of its digits is 1944, while the sum is 25.

The square root of 666331 is about 816.2910020330. The cubic root of 666331 is about 87.3433824201.

Adding to 666331 its reverse (133666), we get a palindrome (799997).

The spelling of 666331 in words is "six hundred sixty-six thousand, three hundred thirty-one".