20021000221 has 8 divisors (see below), whose sum is σ = 20431481400. Its totient is φ = 19614200832.

The previous prime is 20021000201. The next prime is 20021000267. The reversal of 20021000221 is 12200012002.

It can be written as a sum of positive squares in 4 ways, for example, as 4907002500 + 15113997721 = 70050^2 + 122939^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20021000221 - 2¹³ = 20020992029 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20021000198 and 20021000207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021000201) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 909460 + ... + 931213.

It is an arithmetic number, because the mean of its divisors is an integer number (2553935175).

Almost surely, 2^20021000221 is an apocalyptic number.

It is an amenable number.

20021000221 is a deficient number, since it is larger than the sum of its proper divisors (410481179).

20021000221 is a wasteful number, since it uses less digits than its factorization.

20021000221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1840895.

The product of its (nonzero) digits is 16, while the sum is 10.

Adding to 20021000221 its reverse (12200012002), we get a palindrome (32221012223).

The spelling of 20021000221 in words is "twenty billion, twenty-one million, two hundred twenty-one", and thus it is an aban number.