221872 has 30 divisors (see below), whose sum is σ = 501828. Its totient is φ = 94752.

The previous prime is 221849. The next prime is 221873. The reversal of 221872 is 278122.

It is a hoax number, since the sum of its digits (22) 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 (221873) 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, 643 + ... + 925.

2²²¹⁸⁷² 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 221872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (250914).

221872 is an abundant number, since it is smaller than the sum of its proper divisors (279956).

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

221872 is a wasteful number, since it uses less digits than its factorization.

221872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305 (or 292 counting only the distinct ones).

The product of its digits is 448, while the sum is 22.

The square root of 221872 is about 471.0329075553. The cubic root of 221872 is about 60.5388498965.

Adding to 221872 its reverse (278122), we get a palindrome (499994).

The spelling of 221872 in words is "two hundred twenty-one thousand, eight hundred seventy-two".