644554082069 has 2 divisors, whose sum is σ = 644554082070. Its totient is φ = 644554082068.

The previous prime is 644554082063. The next prime is 644554082077. The reversal of 644554082069 is 960280455446.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 538888128100 + 105665953969 = 734090^2 + 325063^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644554082069 is a prime.

It is a super-3 number, since 3×644554082069³ (a number of 36 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 644554082069.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644554082063) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322277041034 + 322277041035.

It is an arithmetic number, because the mean of its divisors is an integer number (322277041035).

Almost surely, 2^644554082069 is an apocalyptic number.

It is an amenable number.

644554082069 is a deficient number, since it is larger than the sum of its proper divisors (1).

644554082069 is an equidigital number, since it uses as much as digits as its factorization.

644554082069 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8294400, while the sum is 53.

The spelling of 644554082069 in words is "six hundred forty-four billion, five hundred fifty-four million, eighty-two thousand, sixty-nine".