221011 has 4 divisors (see below), whose sum is σ = 252592. Its totient is φ = 189432.

The previous prime is 220973. The next prime is 221021. The reversal of 221011 is 110122.

221011 is nontrivially palindromic in base 16.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 110122 = 2 ⋅55061.

It is a cyclic number.

It is not a de Polignac number, because 221011 - 2¹¹ = 218963 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (7), and also a Moran number because the ratio is a prime number: 31573 = 221011 / (2 + 2 + 1 + 0 + 1 + 1).

It is a Duffinian number.

221011 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 220985 and 221003.

It is not an unprimeable number, because it can be changed into a prime (221021) 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, 15780 + ... + 15793.

It is an arithmetic number, because the mean of its divisors is an integer number (63148).

2²²¹⁰¹¹ is an apocalyptic number.

221011 is a deficient number, since it is larger than the sum of its proper divisors (31581).

221011 is an equidigital number, since it uses as much as digits as its factorization.

221011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31580.

The product of its (nonzero) digits is 4, while the sum is 7.

The square root of 221011 is about 470.1180702760. The cubic root of 221011 is about 60.4604390412.

Adding to 221011 its reverse (110122), we get a palindrome (331133).

Subtracting from 221011 its reverse (110122), we obtain a square (110889 = 333²).

It can be divided in two parts, 2210 and 11, that multiplied together give a triangular number (24310 = T₂₂₀).

The spelling of 221011 in words is "two hundred twenty-one thousand, eleven", and thus it is an iban number.