643416444 has 144 divisors (see below), whose sum is σ = 1897668864. Its totient is φ = 181843200.

The previous prime is 643416443. The next prime is 643416451. The reversal of 643416444 is 444614346.

643416444 is a `hidden beast` number, since 6 + 4 + 3 + 4 + 1 + 644 + 4 = 666.

643416444 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 643416399 and 643416408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643416443) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 372567 + ... + 374289.

It is an arithmetic number, because the mean of its divisors is an integer number (13178256).

Almost surely, 2^643416444 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 643416444, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (948834432).

643416444 is an abundant number, since it is smaller than the sum of its proper divisors (1254252420).

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

643416444 is a wasteful number, since it uses less digits than its factorization.

643416444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1808 (or 1803 counting only the distinct ones).

The product of its digits is 110592, while the sum is 36.

The square root of 643416444 is about 25365.6548111812. The cubic root of 643416444 is about 863.3045941183.

The spelling of 643416444 in words is "six hundred forty-three million, four hundred sixteen thousand, four hundred forty-four".