21021010111121 has 4 divisors (see below), whose sum is σ = 21225097588032. Its totient is φ = 20816922634212.

The previous prime is 21021010111097. The next prime is 21021010111247. The reversal of 21021010111121 is 12111101012012.

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 21021010111121 - 2³⁸ = 20746132204177 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21021010111096 and 21021010111105.

It is not an unprimeable number, because it can be changed into a prime (21021010111721) 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, 102043738301 + ... + 102043738506.

It is an arithmetic number, because the mean of its divisors is an integer number (5306274397008).

Almost surely, 2^{21021010111121} is an apocalyptic number.

It is an amenable number.

21021010111121 is a deficient number, since it is larger than the sum of its proper divisors (204087476911).

21021010111121 is a wasteful number, since it uses less digits than its factorization.

21021010111121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204087476910.

The product of its (nonzero) digits is 8, while the sum is 14.

Adding to 21021010111121 its reverse (12111101012012), we get a palindrome (33132111123133).

The spelling of 21021010111121 in words is "twenty-one trillion, twenty-one billion, ten million, one hundred eleven thousand, one hundred twenty-one".