21112121112001 has 4 divisors (see below), whose sum is σ = 21112132756932. Its totient is φ = 21112109467072.

The previous prime is 21112121111987. The next prime is 21112121112067. The reversal of 21112121112001 is 10021112121112.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 9620394008976 + 11491727103025 = 3101676^2 + 3389945^2 .

It is a cyclic number.

It is not a de Polignac number, because 21112121112001 - 2²⁵ = 21112087557569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21112121112701) 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, 2453020 + ... + 6945613.

It is an arithmetic number, because the mean of its divisors is an integer number (5278033189233).

Almost surely, 2^{21112121112001} is an apocalyptic number.

It is an amenable number.

21112121112001 is a deficient number, since it is larger than the sum of its proper divisors (11644931).

21112121112001 is an equidigital number, since it uses as much as digits as its factorization.

21112121112001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11644930.

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

Adding to 21112121112001 its reverse (10021112121112), we get a palindrome (31133233233113).

The spelling of 21112121112001 in words is "twenty-one trillion, one hundred twelve billion, one hundred twenty-one million, one hundred twelve thousand, one".