21121111202111 has 8 divisors (see below), whose sum is σ = 21479986953600. Its totient is φ = 20762265144600.

The previous prime is 21121111202099. The next prime is 21121111202161. The reversal of 21121111202111 is 11120211112112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21121111202111 is a prime.

It is a super-2 number, since 2×21121111202111² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21121111202111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121111202161) 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 7 ways as a sum of consecutive naturals, for example, 5986481 + ... + 8836298.

It is an arithmetic number, because the mean of its divisors is an integer number (2684998369200).

Almost surely, 2^{21121111202111} is an apocalyptic number.

21121111202111 is a deficient number, since it is larger than the sum of its proper divisors (358875751489).

21121111202111 is a wasteful number, since it uses less digits than its factorization.

21121111202111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14846989.

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

Adding to 21121111202111 its reverse (11120211112112), we get a palindrome (32241322314223).

The spelling of 21121111202111 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred eleven million, two hundred two thousand, one hundred eleven".