21111001221121 has 64 divisors (see below), whose sum is σ = 26694995558400. Its totient is φ = 16307398598400.

The previous prime is 21111001221031. The next prime is 21111001221173. The reversal of 21111001221121 is 12112210011112.

It is a de Polignac number, because none of the positive numbers 2^k-21111001221121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21111001221095 and 21111001221104.

It is not an unprimeable number, because it can be changed into a prime (21111001231121) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 19141806 + ... + 20214616.

It is an arithmetic number, because the mean of its divisors is an integer number (417109305600).

Almost surely, 2^{21111001221121} is an apocalyptic number.

It is an amenable number.

21111001221121 is a deficient number, since it is larger than the sum of its proper divisors (5583994337279).

21111001221121 is a wasteful number, since it uses less digits than its factorization.

21111001221121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1072990.

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

Adding to 21111001221121 its reverse (12112210011112), we get a palindrome (33223211232233).

The spelling of 21111001221121 in words is "twenty-one trillion, one hundred eleven billion, one million, two hundred twenty-one thousand, one hundred twenty-one".