644454454446 has 128 divisors (see below), whose sum is σ = 1609318264320. Its totient is φ = 189445132800.

The previous prime is 644454454387. The next prime is 644454454487.

644454454446 is a `hidden beast` number, since 6 + 4 + 4 + 4 + 54 + 4 + 544 + 46 = 666.

644454454446 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 644454454392 and 644454454401.

It is a congruent number.

It is an unprimeable number.

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 in 63 ways as a sum of consecutive naturals, for example, 7363081 + ... + 7450091.

It is an arithmetic number, because the mean of its divisors is an integer number (12572798940).

Almost surely, 2^644454454446 is an apocalyptic number.

644454454446 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 644454454446, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (804659132160).

644454454446 is an abundant number, since it is smaller than the sum of its proper divisors (964863809874).

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

644454454446 is a wasteful number, since it uses less digits than its factorization.

644454454446 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87407 (or 87401 counting only the distinct ones).

The product of its digits is 58982400, while the sum is 54.

The spelling of 644454454446 in words is "six hundred forty-four billion, four hundred fifty-four million, four hundred fifty-four thousand, four hundred forty-six".