21101021200121 has 4 divisors (see below), whose sum is σ = 21201026040144. Its totient is φ = 21001016360100.

The previous prime is 21101021200067. The next prime is 21101021200241. The reversal of 21101021200121 is 12100212010112.

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 21101021200121 - 2¹⁸ = 21101020937977 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21101021200096 and 21101021200105.

It is not an unprimeable number, because it can be changed into a prime (21101021206121) 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, 50002419695 + ... + 50002420116.

It is an arithmetic number, because the mean of its divisors is an integer number (5300256510036).

Almost surely, 2^{21101021200121} is an apocalyptic number.

It is an amenable number.

21101021200121 is a deficient number, since it is larger than the sum of its proper divisors (100004840023).

21101021200121 is a wasteful number, since it uses less digits than its factorization.

21101021200121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100004840022.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21101021200121 its reverse (12100212010112), we get a palindrome (33201233210233).

The spelling of 21101021200121 in words is "twenty-one trillion, one hundred one billion, twenty-one million, two hundred thousand, one hundred twenty-one".