21101221121 has 8 divisors (see below), whose sum is σ = 21142067904. Its totient is φ = 21060401040.

The previous prime is 21101221103. The next prime is 21101221129. The reversal of 21101221121 is 12112210112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21101221121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21101221096 and 21101221105.

It is not an unprimeable number, because it can be changed into a prime (21101221129) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2305871 + ... + 2315003.

It is an arithmetic number, because the mean of its divisors is an integer number (2642758488).

Almost surely, 2^21101221121 is an apocalyptic number.

It is an amenable number.

21101221121 is a deficient number, since it is larger than the sum of its proper divisors (40846783).

21101221121 is an equidigital number, since it uses as much as digits as its factorization.

21101221121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13351.

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

Adding to 21101221121 its reverse (12112210112), we get a palindrome (33213431233).

The spelling of 21101221121 in words is "twenty-one billion, one hundred one million, two hundred twenty-one thousand, one hundred twenty-one".