644554082077 has 2 divisors, whose sum is σ = 644554082078. Its totient is φ = 644554082076.

The previous prime is 644554082069. The next prime is 644554082101. The reversal of 644554082077 is 770280455446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 640785841081 + 3768240996 = 800491^2 + 61386^2 .

It is a cyclic number.

It is not a de Polignac number, because 644554082077 - 2³ = 644554082069 is a prime.

It is a super-3 number, since 3×644554082077³ (a number of 36 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644554082677) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322277041038 + 322277041039.

It is an arithmetic number, because the mean of its divisors is an integer number (322277041039).

Almost surely, 2^644554082077 is an apocalyptic number.

It is an amenable number.

644554082077 is a deficient number, since it is larger than the sum of its proper divisors (1).

644554082077 is an equidigital number, since it uses as much as digits as its factorization.

644554082077 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7526400, while the sum is 52.

The spelling of 644554082077 in words is "six hundred forty-four billion, five hundred fifty-four million, eighty-two thousand, seventy-seven".