21021112112221 has 16 divisors (see below), whose sum is σ = 22915164384000. Its totient is φ = 19167676751808.

The previous prime is 21021112112213. The next prime is 21021112112249. The reversal of 21021112112221 is 12221121112012.

It is a happy number.

It is not a de Polignac number, because 21021112112221 - 2³ = 21021112112213 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 (21021112112821) 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, 21165301 + ... + 22136218.

It is an arithmetic number, because the mean of its divisors is an integer number (1432197774000).

Almost surely, 2^{21021112112221} is an apocalyptic number.

It is an amenable number.

21021112112221 is a deficient number, since it is larger than the sum of its proper divisors (1894052271779).

21021112112221 is a wasteful number, since it uses less digits than its factorization.

21021112112221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43301988.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 21021112112221 its reverse (12221121112012), we get a palindrome (33242233224233).

The spelling of 21021112112221 in words is "twenty-one trillion, twenty-one billion, one hundred twelve million, one hundred twelve thousand, two hundred twenty-one".