21010111211 has 4 divisors (see below), whose sum is σ = 21045904152. Its totient is φ = 20974318272.

The previous prime is 21010111207. The next prime is 21010111219. The reversal of 21010111211 is 11211101012.

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

It is a cyclic number.

It is not a de Polignac number, because 21010111211 - 2² = 21010111207 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21010111192 and 21010111201.

It is not an unprimeable number, because it can be changed into a prime (21010111219) 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 3 ways as a sum of consecutive naturals, for example, 17895590 + ... + 17896763.

It is an arithmetic number, because the mean of its divisors is an integer number (5261476038).

Almost surely, 2^21010111211 is an apocalyptic number.

21010111211 is a deficient number, since it is larger than the sum of its proper divisors (35792941).

21010111211 is an equidigital number, since it uses as much as digits as its factorization.

21010111211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35792940.

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 21010111211 its reverse (11211101012), we get a palindrome (32221212223).

The spelling of 21010111211 in words is "twenty-one billion, ten million, one hundred eleven thousand, two hundred eleven".