21110221021121 has 4 divisors (see below), whose sum is σ = 21126674818992. Its totient is φ = 21093767223252.

The previous prime is 21110221021079. The next prime is 21110221021139. The reversal of 21110221021121 is 12112012201112.

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 a de Polignac number, because none of the positive numbers 2^k-21110221021121 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 21110221021121.

It is not an unprimeable number, because it can be changed into a prime (21110221021151) 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, 8226897011 + ... + 8226899576.

It is an arithmetic number, because the mean of its divisors is an integer number (5281668704748).

Almost surely, 2^{21110221021121} is an apocalyptic number.

It is an amenable number.

21110221021121 is a deficient number, since it is larger than the sum of its proper divisors (16453797871).

21110221021121 is a wasteful number, since it uses less digits than its factorization.

21110221021121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16453797870.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21110221021121 its reverse (12112012201112), we get a palindrome (33222233222233).

The spelling of 21110221021121 in words is "twenty-one trillion, one hundred ten billion, two hundred twenty-one million, twenty-one thousand, one hundred twenty-one".