643784534 has 16 divisors (see below), whose sum is σ = 1010495088. Its totient is φ = 307281312.

The previous prime is 643784527. The next prime is 643784567. The reversal of 643784534 is 435487346.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 78152 + ... + 85995.

It is an arithmetic number, because the mean of its divisors is an integer number (63155943).

Almost surely, 2^643784534 is an apocalyptic number.

643784534 is a deficient number, since it is larger than the sum of its proper divisors (366710554).

643784534 is a wasteful number, since it uses less digits than its factorization.

643784534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164239.

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

The square root of 643784534 is about 25372.9094508296. The cubic root of 643784534 is about 863.4691910975.

The spelling of 643784534 in words is "six hundred forty-three million, seven hundred eighty-four thousand, five hundred thirty-four".