21111100121 has 8 divisors (see below), whose sum is σ = 22086134784. Its totient is φ = 20157976480.

The previous prime is 21111100117. The next prime is 21111100133. The reversal of 21111100121 is 12100111112.

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

It is a cyclic number.

It is not a de Polignac number, because 21111100121 - 2² = 21111100117 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21111100181) 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, 5475785 + ... + 5479638.

It is an arithmetic number, because the mean of its divisors is an integer number (2760766848).

Almost surely, 2^21111100121 is an apocalyptic number.

It is an amenable number.

21111100121 is a deficient number, since it is larger than the sum of its proper divisors (975034663).

21111100121 is a wasteful number, since it uses less digits than its factorization.

21111100121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10955511.

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

Adding to 21111100121 its reverse (12100111112), we get a palindrome (33211211233).

The spelling of 21111100121 in words is "twenty-one billion, one hundred eleven million, one hundred thousand, one hundred twenty-one".