643358864 has 20 divisors (see below), whose sum is σ = 1247845356. Its totient is φ = 321334272.

The previous prime is 643358851. The next prime is 643358893. The reversal of 643358864 is 468853346.

It can be written as a sum of positive squares in 2 ways, for example, as 313573264 + 329785600 = 17708^2 + 18160^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5849 + ... + 36344.

Almost surely, 2^643358864 is an apocalyptic number.

It is an amenable number.

643358864 is a deficient number, since it is larger than the sum of its proper divisors (604486492).

643358864 is a wasteful number, since it uses less digits than its factorization.

643358864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43154 (or 43148 counting only the distinct ones).

The product of its digits is 1658880, while the sum is 47.

The square root of 643358864 is about 25364.5197865049. The cubic root of 643358864 is about 863.2788406777.

The spelling of 643358864 in words is "six hundred forty-three million, three hundred fifty-eight thousand, eight hundred sixty-four".