643728578 has 16 divisors (see below), whose sum is σ = 1008758016. Its totient is φ = 307726320.

The previous prime is 643728559. The next prime is 643728601. The reversal of 643728578 is 875827346.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 57401 + ... + 67692.

It is an arithmetic number, because the mean of its divisors is an integer number (63047376).

Almost surely, 2^643728578 is an apocalyptic number.

643728578 is a deficient number, since it is larger than the sum of its proper divisors (365029438).

643728578 is a wasteful number, since it uses less digits than its factorization.

643728578 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125209.

The product of its digits is 2257920, while the sum is 50.

The square root of 643728578 is about 25371.8067547426. The cubic root of 643728578 is about 863.4441735751. Note that the first 3 decimals are identical.

The spelling of 643728578 in words is "six hundred forty-three million, seven hundred twenty-eight thousand, five hundred seventy-eight".