643389886 has 4 divisors (see below), whose sum is σ = 965084832. Its totient is φ = 321694942.

The previous prime is 643389881. The next prime is 643389889. The reversal of 643389886 is 688983346.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 688983346 = 2 ⋅344491673.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643389881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160847470 + ... + 160847473.

It is an arithmetic number, because the mean of its divisors is an integer number (241271208).

Almost surely, 2^643389886 is an apocalyptic number.

643389886 is a deficient number, since it is larger than the sum of its proper divisors (321694946).

643389886 is a wasteful number, since it uses less digits than its factorization.

643389886 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321694945.

The product of its digits is 5971968, while the sum is 55.

The square root of 643389886 is about 25365.1313026367. The cubic root of 643389886 is about 863.2927158813.

The spelling of 643389886 in words is "six hundred forty-three million, three hundred eighty-nine thousand, eight hundred eighty-six".