21000220212221 has 8 divisors (see below), whose sum is σ = 21553553462784. Its totient is φ = 20448845664480.

The previous prime is 21000220212217. The next prime is 21000220212227. The reversal of 21000220212221 is 12221202200012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21000220212221 - 2² = 21000220212217 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21000220212221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000220212227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 489653981 + ... + 489696866.

It is an arithmetic number, because the mean of its divisors is an integer number (2694194182848).

Almost surely, 2^{21000220212221} is an apocalyptic number.

It is an amenable number.

21000220212221 is a deficient number, since it is larger than the sum of its proper divisors (553333250563).

21000220212221 is an equidigital number, since it uses as much as digits as its factorization.

21000220212221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 979351411.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21000220212221 its reverse (12221202200012), we get a palindrome (33221422412233).

The spelling of 21000220212221 in words is "twenty-one trillion, two hundred twenty million, two hundred twelve thousand, two hundred twenty-one".