644302223 has 2 divisors, whose sum is σ = 644302224. Its totient is φ = 644302222.

The previous prime is 644302213. The next prime is 644302247. The reversal of 644302223 is 322203446.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 644302223 - 2⁴ = 644302207 is a prime.

It is equal to p_33512444 and since 644302223 and 33512444 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 644302192 and 644302201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644302213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322151111 + 322151112.

It is an arithmetic number, because the mean of its divisors is an integer number (322151112).

Almost surely, 2^644302223 is an apocalyptic number.

644302223 is a deficient number, since it is larger than the sum of its proper divisors (1).

644302223 is an equidigital number, since it uses as much as digits as its factorization.

644302223 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6912, while the sum is 26.

The square root of 644302223 is about 25383.1090097332. The cubic root of 644302223 is about 863.7005773837.

Adding to 644302223 its reverse (322203446), we get a palindrome (966505669).

The spelling of 644302223 in words is "six hundred forty-four million, three hundred two thousand, two hundred twenty-three".