643365 has 36 divisors (see below), whose sum is σ = 1222884. Its totient is φ = 311808.

The previous prime is 643303. The next prime is 643369. The reversal of 643365 is 563346.

It can be written as a sum of positive squares in 6 ways, for example, as 6561 + 636804 = 81^2 + 798^2 .

It is not a de Polignac number, because 643365 - 2⁶ = 643301 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

Its product of digits (6480) is a multiple of the sum of its prime divisors (54).

It is a nialpdrome in base 15.

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 643365.

It is not an unprimeable number, because it can be changed into a prime (643369) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 22171 + ... + 22199.

It is an arithmetic number, because the mean of its divisors is an integer number (33969).

2⁶⁴³³⁶⁵ is an apocalyptic number.

It is an amenable number.

643365 is a deficient number, since it is larger than the sum of its proper divisors (579519).

643365 is a wasteful number, since it uses less digits than its factorization.

643365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86 (or 54 counting only the distinct ones).

The product of its digits is 6480, while the sum is 27.

The square root of 643365 is about 802.1003677845. The cubic root of 643365 is about 86.3281585161.

The spelling of 643365 in words is "six hundred forty-three thousand, three hundred sixty-five".