21116121 has 8 divisors (see below), whose sum is σ = 30320640. Its totient is φ = 12994512.

The previous prime is 21116119. The next prime is 21116191. The reversal of 21116121 is 12161112.

It is a happy number.

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

It is not a de Polignac number, because 21116121 - 2¹ = 21116119 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21116121.

It is not an unprimeable number, because it can be changed into a prime (21116191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 270681 + ... + 270758.

It is an arithmetic number, because the mean of its divisors is an integer number (3790080).

Almost surely, 2^21116121 is an apocalyptic number.

It is an amenable number.

21116121 is a deficient number, since it is larger than the sum of its proper divisors (9204519).

21116121 is a wasteful number, since it uses less digits than its factorization.

21116121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 541455.

The product of its digits is 24, while the sum is 15.

The square root of 21116121 is about 4595.2280683335. The cubic root of 21116121 is about 276.4000054801.

Adding to 21116121 its reverse (12161112), we get a palindrome (33277233).

The spelling of 21116121 in words is "twenty-one million, one hundred sixteen thousand, one hundred twenty-one".