644553888355446 has 64 divisors (see below), whose sum is σ = 1327297925866176. Its totient is φ = 208516283596800.

The previous prime is 644553888355439. The next prime is 644553888355459.

It is a happy number.

644553888355446 is nontrivially palindromic in base 10.

It is a super-3 number, since 3×644553888355446³ (a number of 45 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 144805576 + ... + 149190356.

It is an arithmetic number, because the mean of its divisors is an integer number (20739030091659).

Almost surely, 2^{644553888355446} is an apocalyptic number.

644553888355446 is an abundant number, since it is smaller than the sum of its proper divisors (682744037510730).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644553888355446 is a wasteful number, since it uses less digits than its factorization.

644553888355446 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4386497.

The product of its digits is 26542080000, while the sum is 78.

The spelling of 644553888355446 in words is "six hundred forty-four trillion, five hundred fifty-three billion, eight hundred eighty-eight million, three hundred fifty-five thousand, four hundred forty-six".