111121210021 has 4 divisors (see below), whose sum is σ = 111316502700. Its totient is φ = 110925917344.

The previous prime is 111121209977. The next prime is 111121210063. The reversal of 111121210021 is 120012121111.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120012121111 = 89 ⋅1348450799.

It can be written as a sum of positive squares in 2 ways, for example, as 36772281121 + 74348928900 = 191761^2 + 272670^2 .

It is a cyclic number.

It is not a de Polignac number, because 111121210021 - 2¹¹ = 111121207973 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 111121209983 and 111121210010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (111121217021) 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, 97645486 + ... + 97646623.

It is an arithmetic number, because the mean of its divisors is an integer number (27829125675).

Almost surely, 2^111121210021 is an apocalyptic number.

It is an amenable number.

111121210021 is a deficient number, since it is larger than the sum of its proper divisors (195292679).

111121210021 is an equidigital number, since it uses as much as digits as its factorization.

111121210021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195292678.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 111121210021 its reverse (120012121111), we get a palindrome (231133331132).

The spelling of 111121210021 in words is "one hundred eleven billion, one hundred twenty-one million, two hundred ten thousand, twenty-one".