20220021 has 12 divisors (see below), whose sum is σ = 30924972. Its totient is φ = 12686976.

The previous prime is 20220007. The next prime is 20220023. The reversal of 20220021 is 12002202.

It can be written as a sum of positive squares in 2 ways, for example, as 13793796 + 6426225 = 3714^2 + 2535^2 .

It is not a de Polignac number, because 20220021 - 2⁷ = 20219893 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 20219985 and 20220012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20220023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 65926 + ... + 66231.

It is an arithmetic number, because the mean of its divisors is an integer number (2577081).

Almost surely, 2^20220021 is an apocalyptic number.

It is an amenable number.

20220021 is a deficient number, since it is larger than the sum of its proper divisors (10704951).

20220021 is a wasteful number, since it uses less digits than its factorization.

20220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132180 (or 132177 counting only the distinct ones).

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

The square root of 20220021 is about 4496.6677662465. The cubic root of 20220021 is about 272.4335151890.

Adding to 20220021 its reverse (12002202), we get a palindrome (32222223).

The spelling of 20220021 in words is "twenty million, two hundred twenty thousand, twenty-one".