664311623 has 2 divisors, whose sum is σ = 664311624. Its totient is φ = 664311622.

The previous prime is 664311589. The next prime is 664311667. The reversal of 664311623 is 326113466.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 664311623 - 2⁶ = 664311559 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 664311623.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664317623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332155811 + 332155812.

It is an arithmetic number, because the mean of its divisors is an integer number (332155812).

Almost surely, 2^664311623 is an apocalyptic number.

664311623 is a deficient number, since it is larger than the sum of its proper divisors (1).

664311623 is an equidigital number, since it uses as much as digits as its factorization.

664311623 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15552, while the sum is 32.

The square root of 664311623 is about 25774.2434030565. The cubic root of 664311623 is about 872.5505910134.

The spelling of 664311623 in words is "six hundred sixty-four million, three hundred eleven thousand, six hundred twenty-three".