643111400 has 48 divisors (see below), whose sum is σ = 1509799200. Its totient is φ = 254738880.

The previous prime is 643111351. The next prime is 643111423. The reversal of 643111400 is 4111346.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4991 + ... + 36209.

It is an arithmetic number, because the mean of its divisors is an integer number (31454150).

Almost surely, 2^643111400 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 643111400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (754899600).

643111400 is an abundant number, since it is smaller than the sum of its proper divisors (866687800).

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

643111400 is a wasteful number, since it uses less digits than its factorization.

643111400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31338 (or 31329 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 643111400 is about 25359.6411646537. The cubic root of 643111400 is about 863.1681415312.

Adding to 643111400 its reverse (4111346), we get a palindrome (647222746).

The spelling of 643111400 in words is "six hundred forty-three million, one hundred eleven thousand, four hundred".