643543165 has 8 divisors (see below), whose sum is σ = 773284608. Its totient is φ = 514146000.

The previous prime is 643543123. The next prime is 643543171. The reversal of 643543165 is 561345346.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 643543165 - 2¹³ = 643534973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 81937 + ... + 89446.

It is an arithmetic number, because the mean of its divisors is an integer number (96660576).

Almost surely, 2^643543165 is an apocalyptic number.

It is an amenable number.

643543165 is a deficient number, since it is larger than the sum of its proper divisors (129741443).

643543165 is a wasteful number, since it uses less digits than its factorization.

643543165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172139.

The product of its digits is 129600, while the sum is 37.

The square root of 643543165 is about 25368.1525736503. The cubic root of 643543165 is about 863.3612664032.

The spelling of 643543165 in words is "six hundred forty-three million, five hundred forty-three thousand, one hundred sixty-five".