643560 has 64 divisors (see below), whose sum is σ = 2004480. Its totient is φ = 165120.

The previous prime is 643553. The next prime is 643567. The reversal of 643560 is 65346.

643560 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (643553) and next prime (643567).

It is a Harshad number since it is a multiple of its sum of digits (24).

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 643560.

It is not an unprimeable number, because it can be changed into a prime (643567) by changing a digit.

643560 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3634 + ... + 3806.

It is an arithmetic number, because the mean of its divisors is an integer number (31320).

2⁶⁴³⁵⁶⁰ is an apocalyptic number.

643560 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1002240).

643560 is an abundant number, since it is smaller than the sum of its proper divisors (1360920).

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

643560 is a wasteful number, since it uses less digits than its factorization.

643560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218 (or 214 counting only the distinct ones).

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

The square root of 643560 is about 802.2219144352. The cubic root of 643560 is about 86.3368794808.

The spelling of 643560 in words is "six hundred forty-three thousand, five hundred sixty".