643420 has 24 divisors (see below), whose sum is σ = 1378944. Its totient is φ = 252096.

The previous prime is 643403. The next prime is 643421. The reversal of 643420 is 24346.

643420 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 757 + ... + 1363.

It is an arithmetic number, because the mean of its divisors is an integer number (57456).

2⁶⁴³⁴²⁰ is an apocalyptic number.

It is an amenable number.

643420 is an abundant number, since it is smaller than the sum of its proper divisors (735524).

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

643420 is a wasteful number, since it uses less digits than its factorization.

643420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 669 (or 667 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 19.

The square root of 643420 is about 802.1346520379. The cubic root of 643420 is about 86.3306184537.

Adding to 643420 its reverse (24346), we get a palindrome (667766).

The spelling of 643420 in words is "six hundred forty-three thousand, four hundred twenty".