21000111111111 has 32 divisors (see below), whose sum is σ = 31066425446400. Its totient is φ = 12510379075680.

The previous prime is 21000111111107. The next prime is 21000111111121. The reversal of 21000111111111 is 11111111100012.

It is not a de Polignac number, because 21000111111111 - 2² = 21000111111107 is a prime.

21000111111111 is a modest number, since divided by 11111111 gives 210001 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000111111121) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19248720 + ... + 20310426.

It is an arithmetic number, because the mean of its divisors is an integer number (970825795200).

Almost surely, 2^{21000111111111} is an apocalyptic number.

21000111111111 is a deficient number, since it is larger than the sum of its proper divisors (10066314335289).

21000111111111 is a wasteful number, since it uses less digits than its factorization.

21000111111111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1071939.

The product of its (nonzero) digits is 2, while the sum is 12.

Adding to 21000111111111 its reverse (11111111100012), we get a palindrome (32111222211123).

The spelling of 21000111111111 in words is "twenty-one trillion, one hundred eleven million, one hundred eleven thousand, one hundred eleven".