21121201121 has 4 divisors (see below), whose sum is σ = 21318595632. Its totient is φ = 20923806612.

The previous prime is 21121201109. The next prime is 21121201151. The reversal of 21121201121 is 12110212112.

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 21121201121 - 2¹⁰ = 21121200097 is a prime.

It is a super-2 number, since 2×21121201121² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21121201096 and 21121201105.

It is not an unprimeable number, because it can be changed into a prime (21121201151) 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, 98697095 + ... + 98697308.

It is an arithmetic number, because the mean of its divisors is an integer number (5329648908).

Almost surely, 2^21121201121 is an apocalyptic number.

It is an amenable number.

21121201121 is a deficient number, since it is larger than the sum of its proper divisors (197394511).

21121201121 is a wasteful number, since it uses less digits than its factorization.

21121201121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197394510.

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

Adding to 21121201121 its reverse (12110212112), we get a palindrome (33231413233).

The spelling of 21121201121 in words is "twenty-one billion, one hundred twenty-one million, two hundred one thousand, one hundred twenty-one".