21112111010121 has 4 divisors (see below), whose sum is σ = 28149481346832. Its totient is φ = 14074740673412.

The previous prime is 21112111010117. The next prime is 21112111010141. The reversal of 21112111010121 is 12101011121112.

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 21112111010121 - 2² = 21112111010117 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21112111010121.

It is not an unprimeable number, because it can be changed into a prime (21112111010101) 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, 3518685168351 + ... + 3518685168356.

It is an arithmetic number, because the mean of its divisors is an integer number (7037370336708).

Almost surely, 2^{21112111010121} is an apocalyptic number.

It is an amenable number.

21112111010121 is a deficient number, since it is larger than the sum of its proper divisors (7037370336711).

21112111010121 is an equidigital number, since it uses as much as digits as its factorization.

21112111010121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7037370336710.

The product of its (nonzero) digits is 8, while the sum is 15.

Adding to 21112111010121 its reverse (12101011121112), we get a palindrome (33213122131233).

The spelling of 21112111010121 in words is "twenty-one trillion, one hundred twelve billion, one hundred eleven million, ten thousand, one hundred twenty-one".