32221728 has 144 divisors (see below), whose sum is σ = 114319296. Its totient is φ = 8363520.

The previous prime is 32221723. The next prime is 32221753. The reversal of 32221728 is 82712223.

It is a happy number.

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

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (32221723) 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, 21450 + ... + 22902.

It is an arithmetic number, because the mean of its divisors is an integer number (793884).

Almost surely, 2^32221728 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 32221728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (57159648).

32221728 is an abundant number, since it is smaller than the sum of its proper divisors (82097568).

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

32221728 is a wasteful number, since it uses less digits than its factorization.

32221728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1487 (or 1476 counting only the distinct ones).

The product of its digits is 2688, while the sum is 27.

The square root of 32221728 is about 5676.4185892163. The cubic root of 32221728 is about 318.2117967252.

It can be divided in two parts, 3222 and 1728, that added together give a triangular number (4950 = T₉₉).

The spelling of 32221728 in words is "thirty-two million, two hundred twenty-one thousand, seven hundred twenty-eight".