21121111101 has 4 divisors (see below), whose sum is σ = 28161481472. Its totient is φ = 14080740732.

The previous prime is 21121111087. The next prime is 21121111127. The reversal of 21121111101 is 10111112112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21121111101 - 2⁵ = 21121111069 is a prime.

It is a super-2 number, since 2×21121111101² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121111601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3520185181 + ... + 3520185186.

It is an arithmetic number, because the mean of its divisors is an integer number (7040370368).

Almost surely, 2^21121111101 is an apocalyptic number.

It is an amenable number.

21121111101 is a deficient number, since it is larger than the sum of its proper divisors (7040370371).

21121111101 is an equidigital number, since it uses as much as digits as its factorization.

21121111101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7040370370.

The product of its (nonzero) digits is 4, while the sum is 12.

Adding to 21121111101 its reverse (10111112112), we get a palindrome (31232223213).

The spelling of 21121111101 in words is "twenty-one billion, one hundred twenty-one million, one hundred eleven thousand, one hundred one".