20200020021 has 6 divisors (see below), whose sum is σ = 29177806710. Its totient is φ = 13466680008.

The previous prime is 20200019971. The next prime is 20200020023. The reversal of 20200020021 is 12002000202.

It can be written as a sum of positive squares in only one way, i.e., 20020835025 + 179184996 = 141495^2 + 13386^2 .

It is not a de Polignac number, because 20200020021 - 2¹³ = 20200011829 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9), and also a Moran number because the ratio is a prime number: 2244446669 = 20200020021 / (2 + 0 + 2 + 0 + 0 + 0 + 2 + 0 + 0 + 2 + 1).

It is a junction number, because it is equal to n+sod(n) for n = 20200019985 and 20200020012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20200020023) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1122223326 + ... + 1122223343.

It is an arithmetic number, because the mean of its divisors is an integer number (4862967785).

Almost surely, 2^20200020021 is an apocalyptic number.

It is an amenable number.

20200020021 is a deficient number, since it is larger than the sum of its proper divisors (8977786689).

20200020021 is a wasteful number, since it uses less digits than its factorization.

20200020021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2244446675 (or 2244446672 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 9.

Adding to 20200020021 its reverse (12002000202), we get a palindrome (32202020223).

The spelling of 20200020021 in words is "twenty billion, two hundred million, twenty thousand, twenty-one".