20021803 has 4 divisors (see below), whose sum is σ = 20712240. Its totient is φ = 19331368.

The previous prime is 20021759. The next prime is 20021821. The reversal of 20021803 is 30812002.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20021803 - 2²¹ = 17924651 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20021843) 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, 345175 + ... + 345232.

It is an arithmetic number, because the mean of its divisors is an integer number (5178060).

Almost surely, 2^20021803 is an apocalyptic number.

20021803 is a deficient number, since it is larger than the sum of its proper divisors (690437).

20021803 is an equidigital number, since it uses as much as digits as its factorization.

20021803 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 690436.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 20021803 is about 4474.5729405162. The cubic root of 20021803 is about 271.5403632501.

Adding to 20021803 its reverse (30812002), we get a palindrome (50833805).

The spelling of 20021803 in words is "twenty million, twenty-one thousand, eight hundred three".