11111220221 has 4 divisors (see below), whose sum is σ = 11198710272. Its totient is φ = 11023730172.

The previous prime is 11111220199. The next prime is 11111220301. The reversal of 11111220221 is 12202211111.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 11111220221 - 2¹⁸ = 11110958077 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11111220196 and 11111220205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11111225221) 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, 43744835 + ... + 43745088.

It is an arithmetic number, because the mean of its divisors is an integer number (2799677568).

Almost surely, 2^11111220221 is an apocalyptic number.

It is an amenable number.

11111220221 is a deficient number, since it is larger than the sum of its proper divisors (87490051).

11111220221 is an equidigital number, since it uses as much as digits as its factorization.

11111220221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87490050.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 11111220221 its reverse (12202211111), we get a palindrome (23313431332).

It can be divided in two parts, 1111 and 1220221, that multiplied together give a palindrome (1355665531).

The spelling of 11111220221 in words is "eleven billion, one hundred eleven million, two hundred twenty thousand, two hundred twenty-one".