421728 has 48 divisors (see below), whose sum is σ = 1161216. Its totient is φ = 133760.

The previous prime is 421727. The next prime is 421739. The reversal of 421728 is 827124.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a junction number, because it is equal to n+sod(n) for n = 421698 and 421707.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (421727) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2113 + ... + 2303.

It is an arithmetic number, because the mean of its divisors is an integer number (24192).

2⁴²¹⁷²⁸ is an apocalyptic number.

421728 is a gapful number since it is divisible by the number (48) 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 421728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (580608).

421728 is an abundant number, since it is smaller than the sum of its proper divisors (739488).

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

421728 is a wasteful number, since it uses less digits than its factorization.

421728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227 (or 219 counting only the distinct ones).

The product of its digits is 896, while the sum is 24.

The square root of 421728 is about 649.4058823263. The cubic root of 421728 is about 74.9912878769.

It can be divided in two parts, 42 and 1728, that added together give a triangular number (1770 = T₅₉).

The spelling of 421728 in words is "four hundred twenty-one thousand, seven hundred twenty-eight".