664400423 has 2 divisors, whose sum is σ = 664400424. Its totient is φ = 664400422.

The previous prime is 664400389. The next prime is 664400437. The reversal of 664400423 is 324004466.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 664400423 - 2²⁶ = 597291559 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664400483) 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, 332200211 + 332200212.

It is an arithmetic number, because the mean of its divisors is an integer number (332200212).

Almost surely, 2^664400423 is an apocalyptic number.

664400423 is a deficient number, since it is larger than the sum of its proper divisors (1).

664400423 is an equidigital number, since it uses as much as digits as its factorization.

664400423 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13824, while the sum is 29.

The square root of 664400423 is about 25775.9659954773. The cubic root of 664400423 is about 872.5894678686.

Adding to 664400423 its reverse (324004466), we get a palindrome (988404889).

The spelling of 664400423 in words is "six hundred sixty-four million, four hundred thousand, four hundred twenty-three".