21001222111011 has 4 divisors (see below), whose sum is σ = 28001629481352. Its totient is φ = 14000814740672.

The previous prime is 21001222111007. The next prime is 21001222111021. The reversal of 21001222111011 is 11011122210012.

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 21001222111011 - 2² = 21001222111007 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21001222111021) 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, 3500203685166 + ... + 3500203685171.

It is an arithmetic number, because the mean of its divisors is an integer number (7000407370338).

Almost surely, 2^{21001222111011} is an apocalyptic number.

21001222111011 is a deficient number, since it is larger than the sum of its proper divisors (7000407370341).

21001222111011 is an equidigital number, since it uses as much as digits as its factorization.

21001222111011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7000407370340.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21001222111011 its reverse (11011122210012), we get a palindrome (32012344321023).

Subtracting from 21001222111011 its reverse (11011122210012), we obtain a palindrome (9990099900999).

The spelling of 21001222111011 in words is "twenty-one trillion, one billion, two hundred twenty-two million, one hundred eleven thousand, eleven".