20022021 has 6 divisors (see below), whose sum is σ = 28920710. Its totient is φ = 13348008.

The previous prime is 20022017. The next prime is 20022043. The reversal of 20022021 is 12022002.

It can be written as a sum of positive squares in only one way, i.e., 14333796 + 5688225 = 3786^2 + 2385^2 .

It is not a de Polignac number, because 20022021 - 2² = 20022017 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: 2224669 = 20022021 / (2 + 0 + 0 + 2 + 2 + 0 + 2 + 1).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20021994 and 20022012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20022011) 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, 1112326 + ... + 1112343.

Almost surely, 2^20022021 is an apocalyptic number.

It is an amenable number.

20022021 is a deficient number, since it is larger than the sum of its proper divisors (8898689).

20022021 is a wasteful number, since it uses less digits than its factorization.

20022021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2224675 (or 2224672 counting only the distinct ones).

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

The square root of 20022021 is about 4474.5973003165. The cubic root of 20022021 is about 271.5413487689.

Adding to 20022021 its reverse (12022002), we get a palindrome (32044023).

The spelling of 20022021 in words is "twenty million, twenty-two thousand, twenty-one".