644026423 has 2 divisors, whose sum is σ = 644026424. Its totient is φ = 644026422.

The previous prime is 644026387. The next prime is 644026459. The reversal of 644026423 is 324620446.

It is a balanced prime because it is at equal distance from previous prime (644026387) and next prime (644026459).

It is a cyclic number.

It is not a de Polignac number, because 644026423 - 2⁹ = 644025911 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644056423) 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, 322013211 + 322013212.

It is an arithmetic number, because the mean of its divisors is an integer number (322013212).

Almost surely, 2^644026423 is an apocalyptic number.

644026423 is a deficient number, since it is larger than the sum of its proper divisors (1).

644026423 is an equidigital number, since it uses as much as digits as its factorization.

644026423 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27648, while the sum is 31.

The square root of 644026423 is about 25377.6756815907. The cubic root of 644026423 is about 863.5773212429.

Adding to 644026423 its reverse (324620446), we get a palindrome (968646869).

The spelling of 644026423 in words is "six hundred forty-four million, twenty-six thousand, four hundred twenty-three".