640558423 has 2 divisors, whose sum is σ = 640558424. Its totient is φ = 640558422.

The previous prime is 640558417. The next prime is 640558483. The reversal of 640558423 is 324855046.

640558423 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 640558423 - 2²⁹ = 103687511 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640558483) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320279211 + 320279212.

It is an arithmetic number, because the mean of its divisors is an integer number (320279212).

Almost surely, 2^640558423 is an apocalyptic number.

640558423 is a deficient number, since it is larger than the sum of its proper divisors (1).

640558423 is an equidigital number, since it uses as much as digits as its factorization.

640558423 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 115200, while the sum is 37.

The square root of 640558423 is about 25309.2556785062. The cubic root of 640558423 is about 862.0244460420.

The spelling of 640558423 in words is "six hundred forty million, five hundred fifty-eight thousand, four hundred twenty-three".