21010110001221 has 16 divisors (see below), whose sum is σ = 30560527918080. Its totient is φ = 12733246702320.

The previous prime is 21010110001219. The next prime is 21010110001247. The reversal of 21010110001221 is 12210001101012.

It is not a de Polignac number, because 21010110001221 - 2¹ = 21010110001219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21010110001197 and 21010110001206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010110001291) 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 15 ways as a sum of consecutive naturals, for example, 1019031 + ... + 6561908.

It is an arithmetic number, because the mean of its divisors is an integer number (1910032994880).

Almost surely, 2^{21010110001221} is an apocalyptic number.

It is an amenable number.

21010110001221 is a deficient number, since it is larger than the sum of its proper divisors (9550417916859).

21010110001221 is a wasteful number, since it uses less digits than its factorization.

21010110001221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7664936.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21010110001221 its reverse (12210001101012), we get a palindrome (33220111102233).

The spelling of 21010110001221 in words is "twenty-one trillion, ten billion, one hundred ten million, one thousand, two hundred twenty-one".