644554484455446 has 96 divisors (see below), whose sum is σ = 1482536443594752. Its totient is φ = 201950937650880.

The previous prime is 644554484455369. The next prime is 644554484455457.

644554484455446 is a `hidden beast` number, since 6 + 4 + 4 + 5 + 54 + 4 + 84 + 4 + 55 + 446 = 666.

644554484455446 is nontrivially palindromic in base 10.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 14839891 + ... + 38850113.

It is an arithmetic number, because the mean of its divisors is an integer number (15443087954112).

Almost surely, 2^{644554484455446} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644554484455446, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (741268221797376).

644554484455446 is an abundant number, since it is smaller than the sum of its proper divisors (837981959139306).

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

644554484455446 is a wasteful number, since it uses less digits than its factorization.

644554484455446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24011378 (or 24011375 counting only the distinct ones).

The product of its digits is 11796480000, while the sum is 72.

The spelling of 644554484455446 in words is "six hundred forty-four trillion, five hundred fifty-four billion, four hundred eighty-four million, four hundred fifty-five thousand, four hundred forty-six".