643963564 has 12 divisors (see below), whose sum is σ = 1127353864. Its totient is φ = 321862464.

The previous prime is 643963559. The next prime is 643963601. The reversal of 643963564 is 465369346.

It is a hoax number, since the sum of its digits (46) coincides with the sum of the digits of its distinct prime factors.

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 3 ways as a sum of consecutive naturals, for example, 17082 + ... + 39745.

Almost surely, 2^643963564 is an apocalyptic number.

It is an amenable number.

643963564 is a deficient number, since it is larger than the sum of its proper divisors (483390300).

643963564 is a wasteful number, since it uses less digits than its factorization.

643963564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59664 (or 59662 counting only the distinct ones).

The product of its digits is 1399680, while the sum is 46.

The square root of 643963564 is about 25376.4371809756. The cubic root of 643963564 is about 863.5492243766.

The spelling of 643963564 in words is "six hundred forty-three million, nine hundred sixty-three thousand, five hundred sixty-four".