643650 has 48 divisors (see below), whose sum is σ = 1827264. Its totient is φ = 146880.

The previous prime is 643649. The next prime is 643651. The reversal of 643650 is 56346.

It is an interprime number because it is at equal distance from previous prime (643649) and next prime (643651).

It is a nialpdrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 643650.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 643650.

It is not an unprimeable number, because it can be changed into a prime (643651) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 744 + ... + 1356.

It is an arithmetic number, because the mean of its divisors is an integer number (38068).

2⁶⁴³⁶⁵⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (913632).

643650 is an abundant number, since it is smaller than the sum of its proper divisors (1183614).

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

643650 is a wasteful number, since it uses less digits than its factorization.

643650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 635 (or 630 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 24.

The square root of 643650 is about 802.2780066785. The cubic root of 643650 is about 86.3409039473.

Adding to 643650 its reverse (56346), we get a palindrome (699996).

The spelling of 643650 in words is "six hundred forty-three thousand, six hundred fifty".