21022012010221 has 4 divisors (see below), whose sum is σ = 21022023234652. Its totient is φ = 21022000785792.

The previous prime is 21022012010171. The next prime is 21022012010257. The reversal of 21022012010221 is 12201021022012.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 3146543822500 + 17875468187721 = 1773850^2 + 4227939^2 .

It is a cyclic number.

It is not a de Polignac number, because 21022012010221 - 2²³ = 21022003621613 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21022012010195 and 21022012010204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21022012010281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2048646 + ... + 6800071.

It is an arithmetic number, because the mean of its divisors is an integer number (5255505808663).

Almost surely, 2^{21022012010221} is an apocalyptic number.

It is an amenable number.

21022012010221 is a deficient number, since it is larger than the sum of its proper divisors (11224431).

21022012010221 is an equidigital number, since it uses as much as digits as its factorization.

21022012010221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11224430.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21022012010221 its reverse (12201021022012), we get a palindrome (33223033032233).

The spelling of 21022012010221 in words is "twenty-one trillion, twenty-two billion, twelve million, ten thousand, two hundred twenty-one".