66331 has 4 divisors (see below), whose sum is σ = 67032. Its totient is φ = 65632.

The previous prime is 66301. The next prime is 66337. The reversal of 66331 is 13366.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 66331 - 2¹¹ = 64283 is a prime.

It is a super-2 number, since 2×66331² = 8799603122, 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 = 66299 and 66308.

It is not an unprimeable number, because it can be changed into a prime (66337) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 181 + ... + 406.

It is an arithmetic number, because the mean of its divisors is an integer number (16758).

2⁶⁶³³¹ is an apocalyptic number.

66331 is a deficient number, since it is larger than the sum of its proper divisors (701).

66331 is a wasteful number, since it uses less digits than its factorization.

66331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 700.

The product of its digits is 324, while the sum is 19.

The square root of 66331 is about 257.5480537686. The cubic root of 66331 is about 40.4798456852.

Adding to 66331 its reverse (13366), we get a palindrome (79697).

The spelling of 66331 in words is "sixty-six thousand, three hundred thirty-one".