21111322121 has 8 divisors (see below), whose sum is σ = 22161696000. Its totient is φ = 20084033520.

The previous prime is 21111322117. The next prime is 21111322129. The reversal of 21111322121 is 12122311112.

It is a happy number.

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 21111322121 - 2² = 21111322117 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21111322121.

It is not an unprimeable number, because it can be changed into a prime (21111322129) 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, 5769446 + ... + 5773103.

It is an arithmetic number, because the mean of its divisors is an integer number (2770212000).

Almost surely, 2^21111322121 is an apocalyptic number.

It is an amenable number.

21111322121 is a deficient number, since it is larger than the sum of its proper divisors (1050373879).

21111322121 is a wasteful number, since it uses less digits than its factorization.

21111322121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11542639.

The product of its digits is 48, while the sum is 17.

Adding to 21111322121 its reverse (12122311112), we get a palindrome (33233633233).

The spelling of 21111322121 in words is "twenty-one billion, one hundred eleven million, three hundred twenty-two thousand, one hundred twenty-one".