21111101211 has 48 divisors (see below), whose sum is σ = 31008749184. Its totient is φ = 12729401856.

The previous prime is 21111101201. The next prime is 21111101213. The reversal of 21111101211 is 11210111112.

It is not a de Polignac number, because 21111101211 - 2¹³ = 21111093019 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21111101213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5793156 + ... + 5796798.

It is an arithmetic number, because the mean of its divisors is an integer number (646015608).

Almost surely, 2^21111101211 is an apocalyptic number.

21111101211 is a deficient number, since it is larger than the sum of its proper divisors (9897647973).

21111101211 is a wasteful number, since it uses less digits than its factorization.

21111101211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3820 (or 3783 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 12.

Adding to 21111101211 its reverse (11210111112), we get a palindrome (32321212323).

Subtracting from 21111101211 its reverse (11210111112), we obtain a palindrome (9900990099).

The spelling of 21111101211 in words is "twenty-one billion, one hundred eleven million, one hundred one thousand, two hundred eleven".