11111221211021 has 4 divisors (see below), whose sum is σ = 11111677792092. Its totient is φ = 11110764629952.

The previous prime is 11111221210967. The next prime is 11111221211023. The reversal of 11111221211021 is 12011212211111.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9007891729225 + 2103329481796 = 3001315^2 + 1450286^2 .

It is a cyclic number.

It is not a de Polignac number, because 11111221211021 - 2²⁶ = 11111154102157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11111221211023) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 228254030 + ... + 228302703.

It is an arithmetic number, because the mean of its divisors is an integer number (2777919448023).

Almost surely, 2^{11111221211021} is an apocalyptic number.

It is an amenable number.

11111221211021 is a deficient number, since it is larger than the sum of its proper divisors (456581071).

11111221211021 is an equidigital number, since it uses as much as digits as its factorization.

11111221211021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 456581070.

The product of its (nonzero) digits is 16, while the sum is 17.

Adding to 11111221211021 its reverse (12011212211111), we get a palindrome (23122433422132).

The spelling of 11111221211021 in words is "eleven trillion, one hundred eleven billion, two hundred twenty-one million, two hundred eleven thousand, twenty-one".