20045021 has 4 divisors (see below), whose sum is σ = 20083872. Its totient is φ = 20006172.

The previous prime is 20045017. The next prime is 20045063. The reversal of 20045021 is 12054002.

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 20045021 - 2² = 20045017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20044987 and 20045005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20045321) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18641 + ... + 19686.

It is an arithmetic number, because the mean of its divisors is an integer number (5020968).

Almost surely, 2^20045021 is an apocalyptic number.

It is an amenable number.

20045021 is a deficient number, since it is larger than the sum of its proper divisors (38851).

20045021 is an equidigital number, since it uses as much as digits as its factorization.

20045021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38850.

The product of its (nonzero) digits is 80, while the sum is 14.

The square root of 20045021 is about 4477.1666263386. The cubic root of 20045021 is about 271.6452853477.

Adding to 20045021 its reverse (12054002), we get a palindrome (32099023).

The spelling of 20045021 in words is "twenty million, forty-five thousand, twenty-one".