643321 has 12 divisors (see below), whose sum is σ = 788880. Its totient is φ = 521640.

The previous prime is 643303. The next prime is 643369. The reversal of 643321 is 123346.

It is not a de Polignac number, because 643321 - 2⁹ = 642809 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a nialpdrome in base 10 and base 15.

It is not an unprimeable number, because it can be changed into a prime (643301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 586 + ... + 1276.

It is an arithmetic number, because the mean of its divisors is an integer number (65740).

2⁶⁴³³²¹ is an apocalyptic number.

It is an amenable number.

643321 is a deficient number, since it is larger than the sum of its proper divisors (145559).

643321 is a wasteful number, since it uses less digits than its factorization.

643321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 724 (or 717 counting only the distinct ones).

The product of its digits is 432, while the sum is 19.

The square root of 643321 is about 802.0729393266. The cubic root of 643321 is about 86.3261904650.

Adding to 643321 its reverse (123346), we get a palindrome (766667).

It can be divided in two parts, 643 and 321, that multiplied together give a triangular number (206403 = T₆₄₂).

The spelling of 643321 in words is "six hundred forty-three thousand, three hundred twenty-one".