21111021201211 has 4 divisors (see below), whose sum is σ = 21111041834800. Its totient is φ = 21111000567624.

The previous prime is 21111021201181. The next prime is 21111021201271. The reversal of 21111021201211 is 11210212011112.

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 21111021201211 - 2⁴³ = 12314928179003 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21111021201271) 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, 8697351 + ... + 10856608.

It is an arithmetic number, because the mean of its divisors is an integer number (5277760458700).

Almost surely, 2^{21111021201211} is an apocalyptic number.

21111021201211 is a deficient number, since it is larger than the sum of its proper divisors (20633589).

21111021201211 is a wasteful number, since it uses less digits than its factorization.

21111021201211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20633588.

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

Adding to 21111021201211 its reverse (11210212011112), we get a palindrome (32321233212323).

The spelling of 21111021201211 in words is "twenty-one trillion, one hundred eleven billion, twenty-one million, two hundred one thousand, two hundred eleven".