641728 has 28 divisors (see below), whose sum is σ = 1312672. Its totient is φ = 311040.

The previous prime is 641713. The next prime is 641747. The reversal of 641728 is 827146.

It is a junction number, because it is equal to n+sod(n) for n = 641696 and 641705.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2233 + ... + 2503.

2⁶⁴¹⁷²⁸ 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 641728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (656336).

641728 is an abundant number, since it is smaller than the sum of its proper divisors (670944).

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

641728 is a wasteful number, since it uses less digits than its factorization.

641728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 320 (or 310 counting only the distinct ones).

The product of its digits is 2688, while the sum is 28.

The square root of 641728 is about 801.0792719825. The cubic root of 641728 is about 86.2548775509.

It can be divided in two parts, 641 and 728, that added together give a square (1369 = 37²).

The spelling of 641728 in words is "six hundred forty-one thousand, seven hundred twenty-eight".