21112021211 has 4 divisors (see below), whose sum is σ = 21179472072. Its totient is φ = 21044570352.

The previous prime is 21112021201. The next prime is 21112021237. The reversal of 21112021211 is 11212021112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21112021211 is a prime.

It is a super-2 number, since 2×21112021211² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21112021201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33724961 + ... + 33725586.

It is an arithmetic number, because the mean of its divisors is an integer number (5294868018).

Almost surely, 2^21112021211 is an apocalyptic number.

21112021211 is a deficient number, since it is larger than the sum of its proper divisors (67450861).

21112021211 is an equidigital number, since it uses as much as digits as its factorization.

21112021211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67450860.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21112021211 its reverse (11212021112), we get a palindrome (32324042323).

Subtracting from 21112021211 its reverse (11212021112), we obtain a palindrome (9900000099).

The spelling of 21112021211 in words is "twenty-one billion, one hundred twelve million, twenty-one thousand, two hundred eleven".