21000020403 has 32 divisors (see below), whose sum is σ = 29867333632. Its totient is φ = 13101004800.

The previous prime is 21000020401. The next prime is 21000020413. The reversal of 21000020403 is 30402000012.

It is not a de Polignac number, because 21000020403 - 2¹ = 21000020401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21000020401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 542163 + ... + 579603.

It is an arithmetic number, because the mean of its divisors is an integer number (933354176).

Almost surely, 2^21000020403 is an apocalyptic number.

21000020403 is a deficient number, since it is larger than the sum of its proper divisors (8867313229).

21000020403 is a wasteful number, since it uses less digits than its factorization.

21000020403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37675.

The product of its (nonzero) digits is 48, while the sum is 12.

Adding to 21000020403 its reverse (30402000012), we get a palindrome (51402020415).

The spelling of 21000020403 in words is "twenty-one billion, twenty thousand, four hundred three".