221472 has 36 divisors (see below), whose sum is σ = 630630. Its totient is φ = 73728.

The previous prime is 221471. The next prime is 221477. The reversal of 221472 is 274122.

It can be written as a sum of positive squares in only one way, i.e., 197136 + 24336 = 444^2 + 156^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nialpdrome in base 12.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 221472.

It is not an unprimeable number, because it can be changed into a prime (221471) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 97 + ... + 672.

2²²¹⁴⁷² 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 221472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (315315).

221472 is an abundant number, since it is smaller than the sum of its proper divisors (409158).

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

221472 is a wasteful number, since it uses less digits than its factorization.

221472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 785 (or 774 counting only the distinct ones).

The product of its digits is 224, while the sum is 18.

The square root of 221472 is about 470.6081172271. The cubic root of 221472 is about 60.5024473659.

Adding to 221472 its reverse (274122), we get a palindrome (495594).

Subtracting 221472 from its reverse (274122), we obtain a triangular number (52650 = T₃₂₄).

The spelling of 221472 in words is "two hundred twenty-one thousand, four hundred seventy-two", and thus it is an iban number.