21201101221111 has 4 divisors (see below), whose sum is σ = 24229829966992. Its totient is φ = 18172372475232.

The previous prime is 21201101221043. The next prime is 21201101221123. The reversal of 21201101221111 is 11112210110212.

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 21201101221111 - 2⁷ = 21201101220983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201101221171) 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, 1514364372930 + ... + 1514364372943.

It is an arithmetic number, because the mean of its divisors is an integer number (6057457491748).

Almost surely, 2^{21201101221111} is an apocalyptic number.

21201101221111 is a deficient number, since it is larger than the sum of its proper divisors (3028728745881).

21201101221111 is an equidigital number, since it uses as much as digits as its factorization.

21201101221111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3028728745880.

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

Adding to 21201101221111 its reverse (11112210110212), we get a palindrome (32313311331323).

The spelling of 21201101221111 in words is "twenty-one trillion, two hundred one billion, one hundred one million, two hundred twenty-one thousand, one hundred eleven".