643896 has 64 divisors (see below), whose sum is σ = 1958400. Its totient is φ = 194400.

The previous prime is 643889. The next prime is 643919. The reversal of 643896 is 698346.

643896 is a `hidden beast` number, since 643 + 8 + 9 + 6 = 666.

643896 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 643896.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 643896.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2241 + ... + 2511.

It is an arithmetic number, because the mean of its divisors is an integer number (30600).

2⁶⁴³⁸⁹⁶ is an apocalyptic number.

643896 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643896, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (979200).

643896 is an abundant number, since it is smaller than the sum of its proper divisors (1314504).

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

643896 is a wasteful number, since it uses less digits than its factorization.

643896 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 297 (or 287 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 643896 is about 802.4313054711. The cubic root of 643896 is about 86.3519022419.

The spelling of 643896 in words is "six hundred forty-three thousand, eight hundred ninety-six".