21111001111121 has 4 divisors (see below), whose sum is σ = 22028870724672. Its totient is φ = 20193131497572.

The previous prime is 21111001111117. The next prime is 21111001111127. The reversal of 21111001111121 is 12111110011112.

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 a cyclic number.

It is not a de Polignac number, because 21111001111121 - 2² = 21111001111117 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21111001111096 and 21111001111105.

It is not an unprimeable number, because it can be changed into a prime (21111001111127) 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, 458934806741 + ... + 458934806786.

It is an arithmetic number, because the mean of its divisors is an integer number (5507217681168).

Almost surely, 2^{21111001111121} is an apocalyptic number.

It is an amenable number.

21111001111121 is a deficient number, since it is larger than the sum of its proper divisors (917869613551).

21111001111121 is an equidigital number, since it uses as much as digits as its factorization.

21111001111121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 917869613550.

The product of its (nonzero) digits is 4, while the sum is 14.

Adding to 21111001111121 its reverse (12111110011112), we get a palindrome (33222111122233).

The spelling of 21111001111121 in words is "twenty-one trillion, one hundred eleven billion, one million, one hundred eleven thousand, one hundred twenty-one".