21221220111011 has 4 divisors (see below), whose sum is σ = 22143881854992. Its totient is φ = 20298558367032.

The previous prime is 21221220110977. The next prime is 21221220111031. The reversal of 21221220111011 is 11011102212212.

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 21221220111011 - 2⁶ = 21221220110947 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221220111031) 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, 461330871956 + ... + 461330872001.

It is an arithmetic number, because the mean of its divisors is an integer number (5535970463748).

Almost surely, 2^{21221220111011} is an apocalyptic number.

21221220111011 is a deficient number, since it is larger than the sum of its proper divisors (922661743981).

21221220111011 is an equidigital number, since it uses as much as digits as its factorization.

21221220111011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 922661743980.

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

Adding to 21221220111011 its reverse (11011102212212), we get a palindrome (32232322323223).

The spelling of 21221220111011 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred twenty million, one hundred eleven thousand, eleven".