11211220021 has 16 divisors (see below), whose sum is σ = 11582906368. Its totient is φ = 10844895600.

The previous prime is 11211220003. The next prime is 11211220049. The reversal of 11211220021 is 12002211211.

11211220021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 11211220021 - 2¹³ = 11211211829 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11211219983 and 11211220010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11211220621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3772066 + ... + 3775036.

It is an arithmetic number, because the mean of its divisors is an integer number (723931648).

Almost surely, 2^11211220021 is an apocalyptic number.

It is an amenable number.

11211220021 is a deficient number, since it is larger than the sum of its proper divisors (371686347).

11211220021 is a wasteful number, since it uses less digits than its factorization.

11211220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3832.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 11211220021 its reverse (12002211211), we get a palindrome (23213431232).

The spelling of 11211220021 in words is "eleven billion, two hundred eleven million, two hundred twenty thousand, twenty-one".