643331400 has 48 divisors (see below), whose sum is σ = 1994329200. Its totient is φ = 171554880.

The previous prime is 643331399. The next prime is 643331411. The reversal of 643331400 is 4133346.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 535510 + ... + 536709.

It is an arithmetic number, because the mean of its divisors is an integer number (41548525).

Almost surely, 2^643331400 is an apocalyptic number.

643331400 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

643331400 is an abundant number, since it is smaller than the sum of its proper divisors (1350997800).

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

643331400 is a wasteful number, since it uses less digits than its factorization.

643331400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1072238 (or 1072229 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 24.

The square root of 643331400 is about 25363.9783945658. The cubic root of 643331400 is about 863.2665564878.

Adding to 643331400 its reverse (4133346), we get a palindrome (647464746).

The spelling of 643331400 in words is "six hundred forty-three million, three hundred thirty-one thousand, four hundred".