21000100021221 has 8 divisors (see below), whose sum is σ = 28017237909024. Its totient is φ = 13991514407120.

The previous prime is 21000100021193. The next prime is 21000100021333. The reversal of 21000100021221 is 12212000100012.

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 21000100021221 - 2⁷ = 21000100021093 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21000100021197 and 21000100021206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000100029221) 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, 2138062695 + ... + 2138072516.

It is an arithmetic number, because the mean of its divisors is an integer number (3502154738628).

Almost surely, 2^{21000100021221} is an apocalyptic number.

It is an amenable number.

21000100021221 is a deficient number, since it is larger than the sum of its proper divisors (7017137887803).

21000100021221 is a wasteful number, since it uses less digits than its factorization.

21000100021221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4276136851.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21000100021221 its reverse (12212000100012), we get a palindrome (33212100121233).

The spelling of 21000100021221 in words is "twenty-one trillion, one hundred million, twenty-one thousand, two hundred twenty-one".