21121111120111 has 4 divisors (see below), whose sum is σ = 22363529421312. Its totient is φ = 19878692818912.

The previous prime is 21121111120099. The next prime is 21121111120117. The reversal of 21121111120111 is 11102111112112.

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

It is a cyclic number.

It is not a de Polignac number, because 21121111120111 - 2¹⁵ = 21121111087343 is a prime.

It is a super-2 number, since 2×21121111120111² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121111120117) 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, 621209150575 + ... + 621209150608.

It is an arithmetic number, because the mean of its divisors is an integer number (5590882355328).

Almost surely, 2^{21121111120111} is an apocalyptic number.

21121111120111 is a deficient number, since it is larger than the sum of its proper divisors (1242418301201).

21121111120111 is a wasteful number, since it uses less digits than its factorization.

21121111120111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1242418301200.

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

Adding to 21121111120111 its reverse (11102111112112), we get a palindrome (32223222232223).

The spelling of 21121111120111 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred eleven million, one hundred twenty thousand, one hundred eleven".