666523331 has 2 divisors, whose sum is σ = 666523332. Its totient is φ = 666523330.

The previous prime is 666523321. The next prime is 666523357. The reversal of 666523331 is 133325666.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 666523331 - 2¹⁸ = 666261187 is a prime.

It is a super-2 number, since 2×666523331² = 888506701534671122, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 666523291 and 666523300.

It is not a weakly prime, because it can be changed into another prime (666523321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333261665 + 333261666.

It is an arithmetic number, because the mean of its divisors is an integer number (333261666).

Almost surely, 2^666523331 is an apocalyptic number.

666523331 is a deficient number, since it is larger than the sum of its proper divisors (1).

666523331 is an equidigital number, since it uses as much as digits as its factorization.

666523331 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 58320, while the sum is 35.

The square root of 666523331 is about 25817.1131422551. The cubic root of 666523331 is about 873.5178526297.

Adding to 666523331 its reverse (133325666), we get a palindrome (799848997).

The spelling of 666523331 in words is "six hundred sixty-six million, five hundred twenty-three thousand, three hundred thirty-one".