221772 has 12 divisors (see below), whose sum is σ = 517496. Its totient is φ = 73920.

The previous prime is 221747. The next prime is 221773. The reversal of 221772 is 277122.

221772 is nontrivially palindromic in base 5.

221772 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (12).

It is a nialpdrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (221773) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9229 + ... + 9252.

2²²¹⁷⁷² is an apocalyptic number.

It is an amenable number.

221772 is an abundant number, since it is smaller than the sum of its proper divisors (295724).

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

221772 is a wasteful number, since it uses less digits than its factorization.

221772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18488 (or 18486 counting only the distinct ones).

The product of its digits is 392, while the sum is 21.

The square root of 221772 is about 470.9267458958. The cubic root of 221772 is about 60.5297533683.

Adding to 221772 its reverse (277122), we get a palindrome (498894).

The spelling of 221772 in words is "two hundred twenty-one thousand, seven hundred seventy-two", and thus it is an iban number.