643611648 has 176 divisors, whose sum is σ = 1803980160. Its totient is φ = 203833344.

The previous prime is 643611641. The next prime is 643611649. The reversal of 643611648 is 846116346.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643611641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9606111 + ... + 9606177.

Almost surely, 2^643611648 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 643611648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (901990080).

643611648 is an abundant number, since it is smaller than the sum of its proper divisors (1160368512).

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

643611648 is a wasteful number, since it uses less digits than its factorization.

643611648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202 (or 184 counting only the distinct ones).

The product of its digits is 82944, while the sum is 39.

The square root of 643611648 is about 25369.5023206999. The cubic root of 643611648 is about 863.3918903384.

The spelling of 643611648 in words is "six hundred forty-three million, six hundred eleven thousand, six hundred forty-eight".