21000120101221 has 8 divisors (see below), whose sum is σ = 21129958805760. Its totient is φ = 20870330081328.

The previous prime is 21000120101189. The next prime is 21000120101237. The reversal of 21000120101221 is 12210102100012.

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 21000120101221 - 2⁵ = 21000120101189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000100101221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11305606 + ... + 13031383.

It is an arithmetic number, because the mean of its divisors is an integer number (2641244850720).

Almost surely, 2^{21000120101221} is an apocalyptic number.

It is an amenable number.

21000120101221 is a deficient number, since it is larger than the sum of its proper divisors (129838704539).

21000120101221 is a wasteful number, since it uses less digits than its factorization.

21000120101221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24342323.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21000120101221 its reverse (12210102100012), we get a palindrome (33210222201233).

The spelling of 21000120101221 in words is "twenty-one trillion, one hundred twenty million, one hundred one thousand, two hundred twenty-one".