21100212111 has 32 divisors (see below), whose sum is σ = 31556060928. Its totient is φ = 12428432640.

The previous prime is 21100212083. The next prime is 21100212131. The reversal of 21100212111 is 11121200112.

It is not a de Polignac number, because 21100212111 - 2¹⁰ = 21100211087 is a prime.

It is a super-2 number, since 2×21100212111² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100212131) 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, 1134856 + ... + 1153298.

It is an arithmetic number, because the mean of its divisors is an integer number (986126904).

Almost surely, 2^21100212111 is an apocalyptic number.

21100212111 is a deficient number, since it is larger than the sum of its proper divisors (10455848817).

21100212111 is a wasteful number, since it uses less digits than its factorization.

21100212111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19431.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21100212111 its reverse (11121200112), we get a palindrome (32221412223).

The spelling of 21100212111 in words is "twenty-one billion, one hundred million, two hundred twelve thousand, one hundred eleven".