111211111210021 has 4 divisors (see below), whose sum is σ = 111216876749100. Its totient is φ = 111205345670944.

The previous prime is 111211111210019. The next prime is 111211111210039. The reversal of 111211111210021 is 120012111112111.

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 29364964913025 + 81846146296996 = 5418945^2 + 9046886^2 .

It is a cyclic number.

It is not a de Polignac number, because 111211111210021 - 2¹ = 111211111210019 is a prime.

It is a super-2 number, since 2×111211111210021² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 111211111209977 and 111211111210004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (111211111210081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2882740606 + ... + 2882779183.

It is an arithmetic number, because the mean of its divisors is an integer number (27804219187275).

Almost surely, 2^{111211111210021} is an apocalyptic number.

It is an amenable number.

111211111210021 is a deficient number, since it is larger than the sum of its proper divisors (5765539079).

111211111210021 is an equidigital number, since it uses as much as digits as its factorization.

111211111210021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5765539078.

The product of its (nonzero) digits is 8, while the sum is 16.

Adding to 111211111210021 its reverse (120012111112111), we get a palindrome (231223222322132).

The spelling of 111211111210021 in words is "one hundred eleven trillion, two hundred eleven billion, one hundred eleven million, two hundred ten thousand, twenty-one".