21021121210211 has 4 divisors (see below), whose sum is σ = 21044195987424. Its totient is φ = 20998046433000.

The previous prime is 21021121210171. The next prime is 21021121210223. The reversal of 21021121210211 is 11201212112012.

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 21021121210211 - 2²² = 21021117015907 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21021121210211.

It is not an unprimeable number, because it can be changed into a prime (21021121210711) 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, 11537387240 + ... + 11537389061.

It is an arithmetic number, because the mean of its divisors is an integer number (5261048996856).

Almost surely, 2^{21021121210211} is an apocalyptic number.

21021121210211 is a deficient number, since it is larger than the sum of its proper divisors (23074777213).

21021121210211 is an equidigital number, since it uses as much as digits as its factorization.

21021121210211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23074777212.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21021121210211 its reverse (11201212112012), we get a palindrome (32222333322223).

The spelling of 21021121210211 in words is "twenty-one trillion, twenty-one billion, one hundred twenty-one million, two hundred ten thousand, two hundred eleven".