11111220021 has 8 divisors (see below), whose sum is σ = 16161774624. Its totient is φ = 6734072720.

The previous prime is 11111220019. The next prime is 11111220037. The reversal of 11111220021 is 12002211111.

11111220021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 11111220021 - 2¹ = 11111220019 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 11111219979 and 11111220006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11111220061) 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 7 ways as a sum of consecutive naturals, for example, 168351786 + ... + 168351851.

It is an arithmetic number, because the mean of its divisors is an integer number (2020221828).

Almost surely, 2^11111220021 is an apocalyptic number.

11111220021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

11111220021 is a deficient number, since it is larger than the sum of its proper divisors (5050554603).

11111220021 is a wasteful number, since it uses less digits than its factorization.

11111220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 336703651.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 11111220021 its reverse (12002211111), we get a palindrome (23113431132).

It can be divided in two parts, 11111 and 220021, that added together give a palindrome (231132).

The spelling of 11111220021 in words is "eleven billion, one hundred eleven million, two hundred twenty thousand, twenty-one".