643487208 has 160 divisors (see below), whose sum is σ = 2023442400. Its totient is φ = 169513344.

The previous prime is 643487203. The next prime is 643487227. The reversal of 643487208 is 802784346.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a self number, because there is not a number n which added to its sum of digits gives 643487208.

It is not an unprimeable number, because it can be changed into a prime (643487203) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 748683 + ... + 749541.

It is an arithmetic number, because the mean of its divisors is an integer number (12646515).

Almost surely, 2^643487208 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 643487208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1011721200).

643487208 is an abundant number, since it is smaller than the sum of its proper divisors (1379955192).

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

643487208 is a wasteful number, since it uses less digits than its factorization.

643487208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 909 (or 884 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 42.

The square root of 643487208 is about 25367.0496510729. The cubic root of 643487208 is about 863.3362421783.

The spelling of 643487208 in words is "six hundred forty-three million, four hundred eighty-seven thousand, two hundred eight".