664040623 has 2 divisors, whose sum is σ = 664040624. Its totient is φ = 664040622.

The previous prime is 664040617. The next prime is 664040687. The reversal of 664040623 is 326040466.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-664040623 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664040123) 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, 332020311 + 332020312.

It is an arithmetic number, because the mean of its divisors is an integer number (332020312).

Almost surely, 2^664040623 is an apocalyptic number.

664040623 is a deficient number, since it is larger than the sum of its proper divisors (1).

664040623 is an equidigital number, since it uses as much as digits as its factorization.

664040623 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20736, while the sum is 31.

The square root of 664040623 is about 25768.9856804648. The cubic root of 664040623 is about 872.4319251327.

The spelling of 664040623 in words is "six hundred sixty-four million, forty thousand, six hundred twenty-three".