66644231 has 2 divisors, whose sum is σ = 66644232. Its totient is φ = 66644230.

The previous prime is 66644213. The next prime is 66644239. The reversal of 66644231 is 13244666.

Together with previous prime (66644213) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66644231 is a prime.

It is a super-2 number, since 2×66644231² = 8882907051162722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66644239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33322115 + 33322116.

It is an arithmetic number, because the mean of its divisors is an integer number (33322116).

Almost surely, 2^66644231 is an apocalyptic number.

66644231 is a deficient number, since it is larger than the sum of its proper divisors (1).

66644231 is an equidigital number, since it uses as much as digits as its factorization.

66644231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20736, while the sum is 32.

The square root of 66644231 is about 8163.5917952823. The cubic root of 66644231 is about 405.4346418492.

Adding to 66644231 its reverse (13244666), we get a palindrome (79888897).

The spelling of 66644231 in words is "sixty-six million, six hundred forty-four thousand, two hundred thirty-one".