21202111211 has 4 divisors (see below), whose sum is σ = 21224500872. Its totient is φ = 21179721552.

The previous prime is 21202111171. The next prime is 21202111253. The reversal of 21202111211 is 11211120212.

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 21202111211 - 2¹⁴ = 21202094827 is a prime.

It is a super-2 number, since 2×21202111211² (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 (21202111291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11193410 + ... + 11195303.

It is an arithmetic number, because the mean of its divisors is an integer number (5306125218).

Almost surely, 2^21202111211 is an apocalyptic number.

21202111211 is a deficient number, since it is larger than the sum of its proper divisors (22389661).

21202111211 is an equidigital number, since it uses as much as digits as its factorization.

21202111211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22389660.

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

Adding to 21202111211 its reverse (11211120212), we get a palindrome (32413231423).

Subtracting from 21202111211 its reverse (11211120212), we obtain a palindrome (9990990999).

The spelling of 21202111211 in words is "twenty-one billion, two hundred two million, one hundred eleven thousand, two hundred eleven".