21331100305 has 4 divisors (see below), whose sum is σ = 25597320372. Its totient is φ = 17064880240.

The previous prime is 21331100293. The next prime is 21331100321. The reversal of 21331100305 is 50300113312.

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

It can be written as a sum of positive squares in 2 ways, for example, as 3002272849 + 18328827456 = 54793^2 + 135384^2 .

It is not a de Polignac number, because 21331100305 - 2¹⁹ = 21330576017 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 2133110026 + ... + 2133110035.

It is an arithmetic number, because the mean of its divisors is an integer number (6399330093).

Almost surely, 2^21331100305 is an apocalyptic number.

It is an amenable number.

21331100305 is a deficient number, since it is larger than the sum of its proper divisors (4266220067).

21331100305 is an equidigital number, since it uses as much as digits as its factorization.

21331100305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4266220066.

The product of its (nonzero) digits is 270, while the sum is 19.

Adding to 21331100305 its reverse (50300113312), we get a palindrome (71631213617).

The spelling of 21331100305 in words is "twenty-one billion, three hundred thirty-one million, one hundred thousand, three hundred five".