21220053021 has 18 divisors (see below), whose sum is σ = 32560262202. Its totient is φ = 13314541440.

The previous prime is 21220052999. The next prime is 21220053031. The reversal of 21220053021 is 12035002212.

It can be written as a sum of positive squares in 3 ways, for example, as 15979740921 + 5240312100 = 126411^2 + 72390^2 .

It is not a de Polignac number, because 21220053021 - 2⁵ = 21220052989 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21220052985 and 21220053003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220053031) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 4076610 + ... + 4081811.

Almost surely, 2^21220053021 is an apocalyptic number.

It is an amenable number.

21220053021 is a deficient number, since it is larger than the sum of its proper divisors (11340209181).

21220053021 is a wasteful number, since it uses less digits than its factorization.

21220053021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8158461 (or 8158441 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

Adding to 21220053021 its reverse (12035002212), we get a palindrome (33255055233).

The spelling of 21220053021 in words is "twenty-one billion, two hundred twenty million, fifty-three thousand, twenty-one".