664043623 has 2 divisors, whose sum is σ = 664043624. Its totient is φ = 664043622.

The previous prime is 664043609. The next prime is 664043629. The reversal of 664043623 is 326340466.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 664043623 - 2²⁹ = 127172711 is a prime.

It is a super-2 number, since 2×664043623² = 881907866493932258, which contains 22 as substring.

It is equal to p_34485460 and since 664043623 and 34485460 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664043629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332021811 + 332021812.

It is an arithmetic number, because the mean of its divisors is an integer number (332021812).

Almost surely, 2^664043623 is an apocalyptic number.

664043623 is a deficient number, since it is larger than the sum of its proper divisors (1).

664043623 is an equidigital number, since it uses as much as digits as its factorization.

664043623 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 62208, while the sum is 34.

The square root of 664043623 is about 25769.0438899079. The cubic root of 664043623 is about 872.4332389538.

The spelling of 664043623 in words is "six hundred sixty-four million, forty-three thousand, six hundred twenty-three".