20022000021 has 6 divisors (see below), whose sum is σ = 28920666710. Its totient is φ = 13348000008.

The previous prime is 20022000017. The next prime is 20022000041. The reversal of 20022000021 is 12000022002.

It can be written as a sum of positive squares in only one way, i.e., 19384992900 + 637007121 = 139230^2 + 25239^2 .

It is not a de Polignac number, because 20022000021 - 2² = 20022000017 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: 2224666669 = 20022000021 / (2 + 0 + 0 + 2 + 2 + 0 + 0 + 0 + 0 + 2 + 1).

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20021999967 and 20022000012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20022000041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1112333326 + ... + 1112333343.

Almost surely, 2^20022000021 is an apocalyptic number.

It is an amenable number.

20022000021 is a deficient number, since it is larger than the sum of its proper divisors (8898666689).

20022000021 is a wasteful number, since it uses less digits than its factorization.

20022000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2224666675 (or 2224666672 counting only the distinct ones).

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

Adding to 20022000021 its reverse (12000022002), we get a palindrome (32022022023).

The spelling of 20022000021 in words is "twenty billion, twenty-two million, twenty-one", and thus it is an aban number and an uban number.