221121211 has 4 divisors (see below), whose sum is σ = 222002424. Its totient is φ = 220240000.

The previous prime is 221121209. The next prime is 221121217. The reversal of 221121211 is 112121122.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 221121211 - 2¹ = 221121209 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221121191 and 221121200.

It is not an unprimeable number, because it can be changed into a prime (221121217) 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, 440230 + ... + 440731.

It is an arithmetic number, because the mean of its divisors is an integer number (55500606).

Almost surely, 2^221121211 is an apocalyptic number.

221121211 is a deficient number, since it is larger than the sum of its proper divisors (881213).

221121211 is an equidigital number, since it uses as much as digits as its factorization.

221121211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 881212.

The product of its digits is 16, while the sum is 13.

The square root of 221121211 is about 14870.1449555813. The cubic root of 221121211 is about 604.7048725623.

Adding to 221121211 its reverse (112121122), we get a palindrome (333242333).

It can be divided in two parts, 22 and 1121211, that multiplied together give a palindrome (24666642).

The spelling of 221121211 in words is "two hundred twenty-one million, one hundred twenty-one thousand, two hundred eleven".