11211243221 has 4 divisors (see below), whose sum is σ = 11232762444. Its totient is φ = 11189724000.

The previous prime is 11211243203. The next prime is 11211243247. The reversal of 11211243221 is 12234211211.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1217242321 + 9994000900 = 34889^2 + 99970^2 .

It is a cyclic number.

It is not a de Polignac number, because 11211243221 - 2¹⁸ = 11210981077 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11211243193 and 11211243202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11211243271) 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, 10758830 + ... + 10759871.

It is an arithmetic number, because the mean of its divisors is an integer number (2808190611).

Almost surely, 2^11211243221 is an apocalyptic number.

It is an amenable number.

11211243221 is a deficient number, since it is larger than the sum of its proper divisors (21519223).

11211243221 is an equidigital number, since it uses as much as digits as its factorization.

11211243221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21519222.

The product of its digits is 192, while the sum is 20.

Adding to 11211243221 its reverse (12234211211), we get a palindrome (23445454432).

The spelling of 11211243221 in words is "eleven billion, two hundred eleven million, two hundred forty-three thousand, two hundred twenty-one".