643320 has 48 divisors (see below), whose sum is σ = 2091960. Its totient is φ = 171456.

The previous prime is 643303. The next prime is 643369. The reversal of 643320 is 23346.

643320 is a `hidden beast` number, since 643 + 3 + 20 = 666.

643320 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nialpdrome in base 10 and base 15.

It is a junction number, because it is equal to n+sod(n) for n = 643293 and 643302.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 643320.

It is an unprimeable number.

643320 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 11 ways as a sum of consecutive naturals, for example, 534 + ... + 1253.

2⁶⁴³³²⁰ is an apocalyptic number.

643320 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

643320 is an abundant number, since it is smaller than the sum of its proper divisors (1448640).

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

643320 is a wasteful number, since it uses less digits than its factorization.

643320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1804 (or 1797 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 18.

The square root of 643320 is about 802.0723159416. The cubic root of 643320 is about 86.3261457355.

Adding to 643320 its reverse (23346), we get a palindrome (666666).

The spelling of 643320 in words is "six hundred forty-three thousand, three hundred twenty".