21020420203 has 2 divisors, whose sum is σ = 21020420204. Its totient is φ = 21020420202.

The previous prime is 21020420191. The next prime is 21020420221. The reversal of 21020420203 is 30202402012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21020420203 - 2⁵ = 21020420171 is a prime.

It is a super-2 number, since 2×21020420203² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21020420293) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510210101 + 10510210102.

It is an arithmetic number, because the mean of its divisors is an integer number (10510210102).

Almost surely, 2^21020420203 is an apocalyptic number.

21020420203 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020420203 is an equidigital number, since it uses as much as digits as its factorization.

21020420203 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 16.

Adding to 21020420203 its reverse (30202402012), we get a palindrome (51222822215).

The spelling of 21020420203 in words is "twenty-one billion, twenty million, four hundred twenty thousand, two hundred three".