21010020012221 has 16 divisors (see below), whose sum is σ = 22336821124800. Its totient is φ = 19705356000000.

The previous prime is 21010020012203. The next prime is 21010020012251. The reversal of 21010020012221 is 12221002001012.

It is a de Polignac number, because none of the positive numbers 2^k-21010020012221 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21010020012196 and 21010020012205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010020012251) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20727221 + ... + 21717221.

It is an arithmetic number, because the mean of its divisors is an integer number (1396051320300).

Almost surely, 2^{21010020012221} is an apocalyptic number.

It is an amenable number.

21010020012221 is a deficient number, since it is larger than the sum of its proper divisors (1326801112579).

21010020012221 is a wasteful number, since it uses less digits than its factorization.

21010020012221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1001180.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21010020012221 its reverse (12221002001012), we get a palindrome (33231022013233).

The spelling of 21010020012221 in words is "twenty-one trillion, ten billion, twenty million, twelve thousand, two hundred twenty-one".