643784543 has 16 divisors (see below), whose sum is σ = 742284000. Its totient is φ = 554222592.

The previous prime is 643784527. The next prime is 643784567. The reversal of 643784543 is 345487346.

It is a cyclic number.

It is not a de Polignac number, because 643784543 - 2⁴ = 643784527 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 643784494 and 643784503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643784573) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24998 + ... + 43731.

It is an arithmetic number, because the mean of its divisors is an integer number (46392750).

Almost surely, 2^643784543 is an apocalyptic number.

643784543 is a deficient number, since it is larger than the sum of its proper divisors (98499457).

643784543 is a wasteful number, since it uses less digits than its factorization.

643784543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68794.

The product of its digits is 967680, while the sum is 44.

The square root of 643784543 is about 25372.9096281842. The cubic root of 643784543 is about 863.4691951212.

It can be divided in two parts, 64378 and 4543, that added together give a cube (68921 = 41³).

The spelling of 643784543 in words is "six hundred forty-three million, seven hundred eighty-four thousand, five hundred forty-three".