644024443 has 2 divisors, whose sum is σ = 644024444. Its totient is φ = 644024442.

The previous prime is 644024417. The next prime is 644024461. The reversal of 644024443 is 344420446.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644024443 - 2¹³ = 644016251 is a prime.

It is not a weakly prime, because it can be changed into another prime (644028443) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322012221 + 322012222.

It is an arithmetic number, because the mean of its divisors is an integer number (322012222).

Almost surely, 2^644024443 is an apocalyptic number.

644024443 is a deficient number, since it is larger than the sum of its proper divisors (1).

644024443 is an equidigital number, since it uses as much as digits as its factorization.

644024443 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36864, while the sum is 31.

The square root of 644024443 is about 25377.6366708959. The cubic root of 644024443 is about 863.5764362457.

Adding to 644024443 its reverse (344420446), we get a palindrome (988444889).

The spelling of 644024443 in words is "six hundred forty-four million, twenty-four thousand, four hundred forty-three".