643318 has 16 divisors (see below), whose sum is σ = 1053360. Its totient is φ = 292896.

The previous prime is 643303. The next prime is 643369. The reversal of 643318 is 813346.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 643292 and 643301.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 2721 + ... + 2947.

It is an arithmetic number, because the mean of its divisors is an integer number (65835).

2⁶⁴³³¹⁸ is an apocalyptic number.

643318 is a deficient number, since it is larger than the sum of its proper divisors (410042).

643318 is a wasteful number, since it uses less digits than its factorization.

643318 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 351.

The product of its digits is 1728, while the sum is 25.

The square root of 643318 is about 802.0710691703. The cubic root of 643318 is about 86.3260562764.

It can be divided in two parts, 643 and 318, that added together give a square (961 = 31²).

The spelling of 643318 in words is "six hundred forty-three thousand, three hundred eighteen".