20042021 has 4 divisors (see below), whose sum is σ = 20059200. Its totient is φ = 20024844.

The previous prime is 20041981. The next prime is 20042041. The reversal of 20042021 is 12024002.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20042021 - 2¹⁰ = 20040997 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20041993 and 20042011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20042041) 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 3 ways as a sum of consecutive naturals, for example, 6701 + ... + 9218.

It is an arithmetic number, because the mean of its divisors is an integer number (5014800).

Almost surely, 2^20042021 is an apocalyptic number.

It is an amenable number.

20042021 is a deficient number, since it is larger than the sum of its proper divisors (17179).

20042021 is a wasteful number, since it uses less digits than its factorization.

20042021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17178.

The product of its (nonzero) digits is 32, while the sum is 11.

The square root of 20042021 is about 4476.8315804819. The cubic root of 20042021 is about 271.6317329130.

Adding to 20042021 its reverse (12024002), we get a palindrome (32066023).

The spelling of 20042021 in words is "twenty million, forty-two thousand, twenty-one".