21121221001111 has 32 divisors (see below), whose sum is σ = 27044413954560. Its totient is φ = 16018953648000.

The previous prime is 21121221001099. The next prime is 21121221001121. The reversal of 21121221001111 is 11110012212112.

It is a cyclic number.

It is not a de Polignac number, because 21121221001111 - 2¹⁵ = 21121220968343 is a prime.

It is a super-2 number, since 2×21121221001111² (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 (21121221001121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 22556896 + ... + 23474581.

It is an arithmetic number, because the mean of its divisors is an integer number (845137936080).

Almost surely, 2^{21121221001111} is an apocalyptic number.

21121221001111 is a deficient number, since it is larger than the sum of its proper divisors (5923192953449).

21121221001111 is a wasteful number, since it uses less digits than its factorization.

21121221001111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46031655.

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

Adding to 21121221001111 its reverse (11110012212112), we get a palindrome (32231233213223).

The spelling of 21121221001111 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred twenty-one million, one thousand, one hundred eleven".