21101101121 has 4 divisors (see below), whose sum is σ = 21102739392. Its totient is φ = 21099462852.

The previous prime is 21101101081. The next prime is 21101101139. The reversal of 21101101121 is 12110110112.

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 a de Polignac number, because none of the positive numbers 2^k-21101101121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21101101321) 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, 799661 + ... + 825626.

It is an arithmetic number, because the mean of its divisors is an integer number (5275684848).

Almost surely, 2^21101101121 is an apocalyptic number.

It is an amenable number.

21101101121 is a deficient number, since it is larger than the sum of its proper divisors (1638271).

21101101121 is a wasteful number, since it uses less digits than its factorization.

21101101121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1638270.

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 21101101121 its reverse (12110110112), we get a palindrome (33211211233).

The spelling of 21101101121 in words is "twenty-one billion, one hundred one million, one hundred one thousand, one hundred twenty-one".