21111002012101 has 4 divisors (see below), whose sum is σ = 21131438607532. Its totient is φ = 21090565416672.

The previous prime is 21111002012099. The next prime is 21111002012131. The reversal of 21111002012101 is 10121020011112.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13692738136900 + 7418263875201 = 3700370^2 + 2723649^2 .

It is a cyclic number.

It is not a de Polignac number, because 21111002012101 - 2¹ = 21111002012099 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111002012131) 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, 10218296166 + ... + 10218298231.

It is an arithmetic number, because the mean of its divisors is an integer number (5282859651883).

Almost surely, 2^{21111002012101} is an apocalyptic number.

It is an amenable number.

21111002012101 is a deficient number, since it is larger than the sum of its proper divisors (20436595431).

21111002012101 is a wasteful number, since it uses less digits than its factorization.

21111002012101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20436595430.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21111002012101 its reverse (10121020011112), we get a palindrome (31232022023213).

The spelling of 21111002012101 in words is "twenty-one trillion, one hundred eleven billion, two million, twelve thousand, one hundred one".