643712 has 32 divisors (see below), whose sum is σ = 1321920. Its totient is φ = 312064.

The previous prime is 643703. The next prime is 643723. The reversal of 643712 is 217346.

It is a tau number, because it is divible by the number of its divisors (32).

Its product of digits (1008) is a multiple of the sum of its prime factors (168).

It is an unprimeable number.

643712 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5963 + ... + 6069.

It is an arithmetic number, because the mean of its divisors is an integer number (41310).

2⁶⁴³⁷¹² is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (660960).

643712 is an abundant number, since it is smaller than the sum of its proper divisors (678208).

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

643712 is a wasteful number, since it uses less digits than its factorization.

643712 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168 (or 156 counting only the distinct ones).

The product of its digits is 1008, while the sum is 23.

The square root of 643712 is about 802.3166457204. The cubic root of 643712 is about 86.3436761393.

The spelling of 643712 in words is "six hundred forty-three thousand, seven hundred twelve".