644528617 has 2 divisors, whose sum is σ = 644528618. Its totient is φ = 644528616.

The previous prime is 644528611. The next prime is 644528629. The reversal of 644528617 is 716825446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 492351721 + 152176896 = 22189^2 + 12336^2 .

It is a cyclic number.

It is not a de Polignac number, because 644528617 - 2¹⁹ = 644004329 is a prime.

It is a super-3 number, since 3×644528617³ (a number of 27 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (644528611) 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, 322264308 + 322264309.

It is an arithmetic number, because the mean of its divisors is an integer number (322264309).

Almost surely, 2^644528617 is an apocalyptic number.

It is an amenable number.

644528617 is a deficient number, since it is larger than the sum of its proper divisors (1).

644528617 is an equidigital number, since it uses as much as digits as its factorization.

644528617 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 322560, while the sum is 43.

The square root of 644528617 is about 25387.5681584511. The cubic root of 644528617 is about 863.8017274980.

The spelling of 644528617 in words is "six hundred forty-four million, five hundred twenty-eight thousand, six hundred seventeen".