11212121221 has 8 divisors (see below), whose sum is σ = 13055624064. Its totient is φ = 9429061200.

The previous prime is 11212121209. The next prime is 11212121233. The reversal of 11212121221 is 12212121211.

It is an interprime number because it is at equal distance from previous prime (11212121209) and next prime (11212121233).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 11212121221 - 2¹⁵ = 11212088453 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 11212121195 and 11212121204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11212121281) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15110305 + ... + 15111046.

It is an arithmetic number, because the mean of its divisors is an integer number (1631953008).

Almost surely, 2^11212121221 is an apocalyptic number.

It is an amenable number.

11212121221 is a deficient number, since it is larger than the sum of its proper divisors (1843502843).

11212121221 is an equidigital number, since it uses as much as digits as its factorization.

11212121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30221411.

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

Adding to 11212121221 its reverse (12212121211), we get a palindrome (23424242432).

The spelling of 11212121221 in words is "eleven billion, two hundred twelve million, one hundred twenty-one thousand, two hundred twenty-one".