21110000000021 has 8 divisors (see below), whose sum is σ = 21626663819544. Its totient is φ = 20593421217280.

The previous prime is 21110000000009. The next prime is 21110000000027. The reversal of 21110000000021 is 12000000001112.

It can be written as a sum of positive squares in 4 ways, for example, as 135560194225 + 20974439805796 = 368185^2 + 4579786^2 .

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 21110000000021 - 2¹⁴ = 21109999983637 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21109999999936 and 21110000000008.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21110000000027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20756486 + ... + 21749751.

It is an arithmetic number, because the mean of its divisors is an integer number (2703332977443).

Almost surely, 2^{21110000000021} is an apocalyptic number.

It is an amenable number.

21110000000021 is a deficient number, since it is larger than the sum of its proper divisors (516663819523).

21110000000021 is a wasteful number, since it uses less digits than its factorization.

21110000000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42518391.

The product of its (nonzero) digits is 4, while the sum is 8.

Adding to 21110000000021 its reverse (12000000001112), we get a palindrome (33110000001133).

The spelling of 21110000000021 in words is "twenty-one trillion, one hundred ten billion, twenty-one", and thus it is an aban number.