643814403456 has 128 divisors (see below), whose sum is σ = 1955165506560. Its totient is φ = 183878369280.

The previous prime is 643814403443. The next prime is 643814403493. The reversal of 643814403456 is 654304418346.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

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 in 15 ways as a sum of consecutive naturals, for example, 7394416 + ... + 7480976.

It is an arithmetic number, because the mean of its divisors is an integer number (15274730520).

Almost surely, 2^643814403456 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643814403456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (977582753280).

643814403456 is an abundant number, since it is smaller than the sum of its proper divisors (1311351103104).

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

643814403456 is a wasteful number, since it uses less digits than its factorization.

643814403456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89352 (or 89340 counting only the distinct ones).

The product of its (nonzero) digits is 3317760, while the sum is 48.

The spelling of 643814403456 in words is "six hundred forty-three billion, eight hundred fourteen million, four hundred three thousand, four hundred fifty-six".