21020000012221 has 4 divisors (see below), whose sum is σ = 24022857156832. Its totient is φ = 18017142867612.

The previous prime is 21020000012171. The next prime is 21020000012233. The reversal of 21020000012221 is 12221000002012.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21020000012221 - 2⁹ = 21020000011709 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 (21020000012281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1501428572295 + ... + 1501428572308.

It is an arithmetic number, because the mean of its divisors is an integer number (6005714289208).

Almost surely, 2^{21020000012221} is an apocalyptic number.

It is an amenable number.

21020000012221 is a deficient number, since it is larger than the sum of its proper divisors (3002857144611).

21020000012221 is an equidigital number, since it uses as much as digits as its factorization.

21020000012221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3002857144610.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21020000012221 its reverse (12221000002012), we get a palindrome (33241000014233).

The spelling of 21020000012221 in words is "twenty-one trillion, twenty billion, twelve thousand, two hundred twenty-one".