643072 has 26 divisors (see below), whose sum is σ = 1294178. Its totient is φ = 319488.

The previous prime is 643061. The next prime is 643073. The reversal of 643072 is 270346.

It can be written as a sum of positive squares in only one way, i.e., 495616 + 147456 = 704^2 + 384^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643073) by changing a digit.

643072 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 (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4018 + ... + 4174.

2⁶⁴³⁰⁷² 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 643072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (647089).

643072 is an abundant number, since it is smaller than the sum of its proper divisors (651106).

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

643072 is an equidigital number, since it uses as much as digits as its factorization.

643072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181 (or 159 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 22.

The square root of 643072 is about 801.9177015131. The cubic root of 643072 is about 86.3150513938.

It can be divided in two parts, 64 and 3072, that added together give a square (3136 = 56²).

The spelling of 643072 in words is "six hundred forty-three thousand, seventy-two".