643814886 has 128 divisors (see below), whose sum is σ = 1617154560. Its totient is φ = 167961600.

The previous prime is 643814881. The next prime is 643814909. The reversal of 643814886 is 688418346.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643814881) by changing a digit.

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 63 ways as a sum of consecutive naturals, for example, 1189776 + ... + 1190316.

It is an arithmetic number, because the mean of its divisors is an integer number (12634020).

Almost surely, 2^643814886 is an apocalyptic number.

643814886 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 643814886, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (808577280).

643814886 is an abundant number, since it is smaller than the sum of its proper divisors (973339674).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

643814886 is a wasteful number, since it uses less digits than its factorization.

643814886 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 662.

The product of its digits is 884736, while the sum is 48.

The square root of 643814886 is about 25373.5075620222. The cubic root of 643814886 is about 863.4827606505.

The spelling of 643814886 in words is "six hundred forty-three million, eight hundred fourteen thousand, eight hundred eighty-six".