643105400 has 144 divisors (see below), whose sum is σ = 1755691200. Its totient is φ = 218426880.

The previous prime is 643105387. The next prime is 643105409. The reversal of 643105400 is 4501346.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643105409) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1342361 + ... + 1342839.

It is an arithmetic number, because the mean of its divisors is an integer number (12192300).

Almost surely, 2^643105400 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 643105400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (877845600).

643105400 is an abundant number, since it is smaller than the sum of its proper divisors (1112585800).

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

643105400 is a wasteful number, since it uses less digits than its factorization.

643105400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 646 (or 630 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 643105400 is about 25359.5228661740. The cubic root of 643105400 is about 863.1654571725.

Adding to 643105400 its reverse (4501346), we get a palindrome (647606746).

The spelling of 643105400 in words is "six hundred forty-three million, one hundred five thousand, four hundred".