21010111121 has 4 divisors (see below), whose sum is σ = 21064968192. Its totient is φ = 20955254052.

The previous prime is 21010111103. The next prime is 21010111163. The reversal of 21010111121 is 12111101012.

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 21010111121 - 2¹⁴ = 21010094737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21010116121) 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, 27427961 + ... + 27428726.

It is an arithmetic number, because the mean of its divisors is an integer number (5266242048).

Almost surely, 2^21010111121 is an apocalyptic number.

It is an amenable number.

21010111121 is a deficient number, since it is larger than the sum of its proper divisors (54857071).

21010111121 is an equidigital number, since it uses as much as digits as its factorization.

21010111121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54857070.

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 21010111121 its reverse (12111101012), we get a palindrome (33121212133).

The spelling of 21010111121 in words is "twenty-one billion, ten million, one hundred eleven thousand, one hundred twenty-one".