643042400 has 432 divisors, whose sum is σ = 2152799712. Its totient is φ = 182476800.

The previous prime is 643042381. The next prime is 643042423. The reversal of 643042400 is 4240346.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 8808764 + ... + 8808836.

Almost surely, 2^643042400 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 643042400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1076399856).

643042400 is an abundant number, since it is smaller than the sum of its proper divisors (1509757312).

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

643042400 is a wasteful number, since it uses less digits than its factorization.

643042400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135 (or 111 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 23.

The square root of 643042400 is about 25358.2806988171. The cubic root of 643042400 is about 863.1372703986.

Adding to 643042400 its reverse (4240346), we get a palindrome (647282746).

The spelling of 643042400 in words is "six hundred forty-three million, forty-two thousand, four hundred".