11131121221 has 16 divisors (see below), whose sum is σ = 12357043776. Its totient is φ = 9942400000.

The previous prime is 11131121213. The next prime is 11131121257. The reversal of 11131121221 is 12212113111.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 11131121221 - 2³ = 11131121213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 11131121195 and 11131121204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11131121021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 107301 + ... + 183781.

It is an arithmetic number, because the mean of its divisors is an integer number (772315236).

Almost surely, 2^11131121221 is an apocalyptic number.

11131121221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

11131121221 is a deficient number, since it is larger than the sum of its proper divisors (1225922555).

11131121221 is a wasteful number, since it uses less digits than its factorization.

11131121221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76724.

The product of its digits is 24, while the sum is 16.

Adding to 11131121221 its reverse (12212113111), we get a palindrome (23343234332).

The spelling of 11131121221 in words is "eleven billion, one hundred thirty-one million, one hundred twenty-one thousand, two hundred twenty-one".