643513420 has 48 divisors (see below), whose sum is σ = 1488878496. Its totient is φ = 231680000.

The previous prime is 643513379. The next prime is 643513441. The reversal of 643513420 is 24315346.

643513420 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7740 + ... + 36700.

It is an arithmetic number, because the mean of its divisors is an integer number (31018302).

Almost surely, 2^643513420 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 643513420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (744439248).

643513420 is an abundant number, since it is smaller than the sum of its proper divisors (845365076).

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

643513420 is a wasteful number, since it uses less digits than its factorization.

643513420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29082 (or 29080 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 28.

The square root of 643513420 is about 25367.5663002977. The cubic root of 643513420 is about 863.3479644846.

Adding to 643513420 its reverse (24315346), we get a palindrome (667828766).

The spelling of 643513420 in words is "six hundred forty-three million, five hundred thirteen thousand, four hundred twenty".