643355555 has 8 divisors (see below), whose sum is σ = 796930944. Its totient is φ = 498081600.

The previous prime is 643355549. The next prime is 643355567. The reversal of 643355555 is 555553346.

643355555 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 643355555 - 2⁸ = 643355299 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2075186 + ... + 2075495.

It is an arithmetic number, because the mean of its divisors is an integer number (99616368).

Almost surely, 2^643355555 is an apocalyptic number.

643355555 is a deficient number, since it is larger than the sum of its proper divisors (153575389).

643355555 is a wasteful number, since it uses less digits than its factorization.

643355555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4150717.

The product of its digits is 675000, while the sum is 41.

The square root of 643355555 is about 25364.4545575102. The cubic root of 643355555 is about 863.2773606356.

The spelling of 643355555 in words is "six hundred forty-three million, three hundred fifty-five thousand, five hundred fifty-five".