21121111105 has 8 divisors (see below), whose sum is σ = 25374238632. Its totient is φ = 16877618688.

The previous prime is 21121111087. The next prime is 21121111127. The reversal of 21121111105 is 50111112112.

It can be written as a sum of positive squares in 4 ways, for example, as 1567843216 + 19553267889 = 39596^2 + 139833^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21121111105 - 2⁷ = 21121110977 is a prime.

It is a super-2 number, since 2×21121111105² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2403952 + ... + 2412721.

It is an arithmetic number, because the mean of its divisors is an integer number (3171779829).

Almost surely, 2^21121111105 is an apocalyptic number.

It is an amenable number.

21121111105 is a deficient number, since it is larger than the sum of its proper divisors (4253127527).

21121111105 is an equidigital number, since it uses as much as digits as its factorization.

21121111105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4817555.

The product of its (nonzero) digits is 20, while the sum is 16.

Adding to 21121111105 its reverse (50111112112), we get a palindrome (71232223217).

The spelling of 21121111105 in words is "twenty-one billion, one hundred twenty-one million, one hundred eleven thousand, one hundred five".