211220111221 has 12 divisors (see below), whose sum is σ = 254768067552. Its totient is φ = 171517080744.

The previous prime is 211220111197. The next prime is 211220111237. The reversal of 211220111221 is 122111022112.

It is not a de Polignac number, because 211220111221 - 2¹⁷ = 211219980149 is a prime.

It is a super-2 number, since 2×211220111221² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 211220111195 and 211220111204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211220111261) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 41790135 + ... + 41795188.

It is an arithmetic number, because the mean of its divisors is an integer number (21230672296).

Almost surely, 2^211220111221 is an apocalyptic number.

It is an amenable number.

211220111221 is a deficient number, since it is larger than the sum of its proper divisors (43547956331).

211220111221 is an equidigital number, since it uses as much as digits as its factorization.

211220111221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83585368 (or 83585349 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 211220111221 its reverse (122111022112), we get a palindrome (333331133333).

The spelling of 211220111221 in words is "two hundred eleven billion, two hundred twenty million, one hundred eleven thousand, two hundred twenty-one".