644554082072 has 8 divisors (see below), whose sum is σ = 1208538903900. Its totient is φ = 322277041032.

The previous prime is 644554082069. The next prime is 644554082077. The reversal of 644554082072 is 270280455446.

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-3 number, since 3×644554082072³ (a number of 36 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644554082077) 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, 40284630122 + ... + 40284630137.

Almost surely, 2^644554082072 is an apocalyptic number.

It is an amenable number.

644554082072 is a deficient number, since it is larger than the sum of its proper divisors (563984821828).

644554082072 is a wasteful number, since it uses less digits than its factorization.

644554082072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80569260265 (or 80569260261 counting only the distinct ones).

The product of its (nonzero) digits is 2150400, while the sum is 47.

The spelling of 644554082072 in words is "six hundred forty-four billion, five hundred fifty-four million, eighty-two thousand, seventy-two".