21221220111211 has 4 divisors (see below), whose sum is σ = 21222387349024. Its totient is φ = 21220052873400.

The previous prime is 21221220111187. The next prime is 21221220111233. The reversal of 21221220111211 is 11211102212212.

It is a happy number.

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 21221220111211 - 2¹³ = 21221220103019 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221220171211) 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, 583591635 + ... + 583627996.

It is an arithmetic number, because the mean of its divisors is an integer number (5305596837256).

Almost surely, 2^{21221220111211} is an apocalyptic number.

21221220111211 is a deficient number, since it is larger than the sum of its proper divisors (1167237813).

21221220111211 is a wasteful number, since it uses less digits than its factorization.

21221220111211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1167237812.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 21221220111211 its reverse (11211102212212), we get a palindrome (32432322323423).

The spelling of 21221220111211 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred twenty million, one hundred eleven thousand, two hundred eleven".