21111111000101 has 4 divisors (see below), whose sum is σ = 21111122390604. Its totient is φ = 21111099609600.

The previous prime is 21111111000029. The next prime is 21111111000113. The reversal of 21111111000101 is 10100011111112.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 17713374543076 + 3397736457025 = 4208726^2 + 1843295^2 .

It is a cyclic number.

It is not a de Polignac number, because 21111111000101 - 2¹⁴ = 21111110983717 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 (21111111000131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2200220 + ... + 6860261.

It is an arithmetic number, because the mean of its divisors is an integer number (5277780597651).

Almost surely, 2^{21111111000101} is an apocalyptic number.

It is an amenable number.

21111111000101 is a deficient number, since it is larger than the sum of its proper divisors (11390503).

21111111000101 is an equidigital number, since it uses as much as digits as its factorization.

21111111000101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11390502.

The product of its (nonzero) digits is 2, while the sum is 11.

Adding to 21111111000101 its reverse (10100011111112), we get a palindrome (31211122111213).

The spelling of 21111111000101 in words is "twenty-one trillion, one hundred eleven billion, one hundred eleven million, one hundred one", and thus it is an aban number.