664043531 has 2 divisors, whose sum is σ = 664043532. Its totient is φ = 664043530.

The previous prime is 664043459. The next prime is 664043533. The reversal of 664043531 is 135340466.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 664043531 - 2¹⁸ = 663781387 is a prime.

It is a super-2 number, since 2×664043531² = 881907622125895922, which contains 22 as substring.

Together with 664043533, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (664043533) 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 as a sum of consecutive naturals, namely, 332021765 + 332021766.

It is an arithmetic number, because the mean of its divisors is an integer number (332021766).

Almost surely, 2^664043531 is an apocalyptic number.

664043531 is a deficient number, since it is larger than the sum of its proper divisors (1).

664043531 is an equidigital number, since it uses as much as digits as its factorization.

664043531 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 32.

The square root of 664043531 is about 25769.0421048203. The cubic root of 664043531 is about 872.4331986634.

Adding to 664043531 its reverse (135340466), we get a palindrome (799383997).

It can be divided in two parts, 6640435 and 31, that added together give a palindrome (6640466).

The spelling of 664043531 in words is "six hundred sixty-four million, forty-three thousand, five hundred thirty-one".