643311420 has 96 divisors (see below), whose sum is σ = 1842462720. Its totient is φ = 167673600.

The previous prime is 643311407. The next prime is 643311463. The reversal of 643311420 is 24113346.

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, 502341 + ... + 503619.

It is an arithmetic number, because the mean of its divisors is an integer number (19192320).

Almost surely, 2^643311420 is an apocalyptic number.

643311420 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643311420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (921231360).

643311420 is an abundant number, since it is smaller than the sum of its proper divisors (1199151300).

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

643311420 is a wasteful number, since it uses less digits than its factorization.

643311420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1475 (or 1473 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 24.

The square root of 643311420 is about 25363.5845258512. The cubic root of 643311420 is about 863.2576195467.

Adding to 643311420 its reverse (24113346), we get a palindrome (667424766).

The spelling of 643311420 in words is "six hundred forty-three million, three hundred eleven thousand, four hundred twenty".