644347441 has 2 divisors, whose sum is σ = 644347442. Its totient is φ = 644347440.

The previous prime is 644347411. The next prime is 644347523. The reversal of 644347441 is 144743446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 596336400 + 48011041 = 24420^2 + 6929^2 .

It is a cyclic number.

It is not a de Polignac number, because 644347441 - 2⁹ = 644346929 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 644347441.

It is not a weakly prime, because it can be changed into another prime (644347411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322173720 + 322173721.

It is an arithmetic number, because the mean of its divisors is an integer number (322173721).

Almost surely, 2^644347441 is an apocalyptic number.

It is an amenable number.

644347441 is a deficient number, since it is larger than the sum of its proper divisors (1).

644347441 is an equidigital number, since it uses as much as digits as its factorization.

644347441 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 129024, while the sum is 37.

The square root of 644347441 is about 25383.9997045383. Note that the first 3 decimals coincide. The cubic root of 644347441 is about 863.7207821353.

The spelling of 644347441 in words is "six hundred forty-four million, three hundred forty-seven thousand, four hundred forty-one".