643328 has 36 divisors (see below), whose sum is σ = 1471680. Its totient is φ = 274944.

The previous prime is 643303. The next prime is 643369. The reversal of 643328 is 823346.

It is a hoax number, since the sum of its digits (26) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 643297 and 643306.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1613 + ... + 1971.

It is an arithmetic number, because the mean of its divisors is an integer number (40880).

2⁶⁴³³²⁸ 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 643328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (735840).

643328 is an abundant number, since it is smaller than the sum of its proper divisors (828352).

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

643328 is an equidigital number, since it uses as much as digits as its factorization.

643328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 382 (or 368 counting only the distinct ones).

The product of its digits is 3456, while the sum is 26.

The square root of 643328 is about 802.0773030076. The cubic root of 643328 is about 86.3265035700.

It can be divided in two parts, 6 and 43328, that added together give a palindrome (43334).

The spelling of 643328 in words is "six hundred forty-three thousand, three hundred twenty-eight".