644597113 has 2 divisors, whose sum is σ = 644597114. Its totient is φ = 644597112.

The previous prime is 644597111. The next prime is 644597131. The reversal of 644597113 is 311795446.

Together with next prime (644597131) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 644499769 + 97344 = 25387^2 + 312^2 .

It is a cyclic number.

It is not a de Polignac number, because 644597113 - 2¹ = 644597111 is a prime.

Together with 644597111, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (644597111) 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, 322298556 + 322298557.

It is an arithmetic number, because the mean of its divisors is an integer number (322298557).

Almost surely, 2^644597113 is an apocalyptic number.

It is an amenable number.

644597113 is a deficient number, since it is larger than the sum of its proper divisors (1).

644597113 is an equidigital number, since it uses as much as digits as its factorization.

644597113 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 90720, while the sum is 40.

The square root of 644597113 is about 25388.9171293303. The cubic root of 644597113 is about 863.8323260191.

The spelling of 644597113 in words is "six hundred forty-four million, five hundred ninety-seven thousand, one hundred thirteen".