644975203 has 2 divisors, whose sum is σ = 644975204. Its totient is φ = 644975202.

The previous prime is 644975183. The next prime is 644975207. The reversal of 644975203 is 302579446.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644975203 - 2¹⁷ = 644844131 is a prime.

It is not a weakly prime, because it can be changed into another prime (644975207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322487601 + 322487602.

It is an arithmetic number, because the mean of its divisors is an integer number (322487602).

Almost surely, 2^644975203 is an apocalyptic number.

644975203 is a deficient number, since it is larger than the sum of its proper divisors (1).

644975203 is an equidigital number, since it uses as much as digits as its factorization.

644975203 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 181440, while the sum is 40.

The square root of 644975203 is about 25396.3620032476. The cubic root of 644975203 is about 864.0011873233.

The spelling of 644975203 in words is "six hundred forty-four million, nine hundred seventy-five thousand, two hundred three".