21111020121109 has 4 divisors (see below), whose sum is σ = 21111029861760. Its totient is φ = 21111010380460.

The previous prime is 21111020121089. The next prime is 21111020121143. The reversal of 21111020121109 is 90112102011112.

It is a happy number.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21111020121109 - 2²⁷ = 21110885903381 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21111020121109.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111020121179) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12282 + ... + 6497860.

It is an arithmetic number, because the mean of its divisors is an integer number (5277757465440).

Almost surely, 2^{21111020121109} is an apocalyptic number.

It is an amenable number.

21111020121109 is a deficient number, since it is larger than the sum of its proper divisors (9740651).

21111020121109 is an equidigital number, since it uses as much as digits as its factorization.

21111020121109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9740650.

The product of its (nonzero) digits is 72, while the sum is 22.

The spelling of 21111020121109 in words is "twenty-one trillion, one hundred eleven billion, twenty million, one hundred twenty-one thousand, one hundred nine".