11111210021 has 12 divisors (see below), whose sum is σ = 11211748044. Its totient is φ = 11011507200.

The previous prime is 11111210009. The next prime is 11111210041. The reversal of 11111210021 is 12001211111.

It can be written as a sum of positive squares in 2 ways, for example, as 7536844225 + 3574365796 = 86815^2 + 59786^2 .

It is not a de Polignac number, because 11111210021 - 2²⁶ = 11044101157 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11111209984 and 11111210011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11111210041) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17333861 + ... + 17334501.

It is an arithmetic number, because the mean of its divisors is an integer number (934312337).

Almost surely, 2^11111210021 is an apocalyptic number.

It is an amenable number.

11111210021 is a deficient number, since it is larger than the sum of its proper divisors (100538023).

11111210021 is an frugal number, since it uses more digits than its factorization.

11111210021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1540 (or 1361 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 11111210021 its reverse (12001211111), we get a palindrome (23112421132).

The spelling of 11111210021 in words is "eleven billion, one hundred eleven million, two hundred ten thousand, twenty-one".