84421728 has 144 divisors (see below), whose sum is σ = 260756496. Its totient is φ = 25804800.

The previous prime is 84421723. The next prime is 84421741. The reversal of 84421728 is 82712448.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

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

It is a junction number, because it is equal to n+sod(n) for n = 84421692 and 84421701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (84421723) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 210328 + ... + 210728.

It is an arithmetic number, because the mean of its divisors is an integer number (1810809).

Almost surely, 2^84421728 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 84421728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (130378248).

84421728 is an abundant number, since it is smaller than the sum of its proper divisors (176334768).

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

84421728 is a wasteful number, since it uses less digits than its factorization.

84421728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 477 (or 466 counting only the distinct ones).

The product of its digits is 28672, while the sum is 36.

The square root of 84421728 is about 9188.1297335203. The cubic root of 84421728 is about 438.6836137900.

The spelling of 84421728 in words is "eighty-four million, four hundred twenty-one thousand, seven hundred twenty-eight".