11211121220 has 24 divisors (see below), whose sum is σ = 25354382424. Its totient is φ = 4139490816.

The previous prime is 11211121199. The next prime is 11211121277. The reversal of 11211121220 is 2212111211.

It can be written as a sum of positive squares in 4 ways, for example, as 212984836 + 10998136384 = 14594^2 + 104872^2 .

It is a junction number, because it is equal to n+sod(n) for n = 11211121195 and 11211121204.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21559589 + ... + 21560108.

It is an arithmetic number, because the mean of its divisors is an integer number (1056432601).

Almost surely, 2^11211121220 is an apocalyptic number.

11211121220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

11211121220 is an abundant number, since it is smaller than the sum of its proper divisors (14143261204).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

11211121220 is a wasteful number, since it uses less digits than its factorization.

11211121220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43119719 (or 43119717 counting only the distinct ones).

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

Adding to 11211121220 its reverse (2212111211), we get a palindrome (13423232431).

It can be divided in two parts, 112111 and 21220, that added together give a palindrome (133331).

The spelling of 11211121220 in words is "eleven billion, two hundred eleven million, one hundred twenty-one thousand, two hundred twenty".