21000012012221 has 8 divisors (see below), whose sum is σ = 23699073117600. Its totient is φ = 18432612424240.

The previous prime is 21000012012193. The next prime is 21000012012271. The reversal of 21000012012221 is 12221021000012.

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 21000012012221 - 2¹⁸ = 21000011750077 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21000012012196 and 21000012012205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000012012271) 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, 32915379011 + ... + 32915379648.

It is an arithmetic number, because the mean of its divisors is an integer number (2962384139700).

Almost surely, 2^{21000012012221} is an apocalyptic number.

It is an amenable number.

21000012012221 is a deficient number, since it is larger than the sum of its proper divisors (2699061105379).

21000012012221 is a wasteful number, since it uses less digits than its factorization.

21000012012221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65830758699.

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

Adding to 21000012012221 its reverse (12221021000012), we get a palindrome (33221033012233).

It can be divided in two parts, 210000 and 12012221, that added together give a palindrome (12222221).

The spelling of 21000012012221 in words is "twenty-one trillion, twelve million, twelve thousand, two hundred twenty-one".