21003220305 has 12 divisors (see below), whose sum is σ = 36405581940. Its totient is φ = 11201717472.

The previous prime is 21003220297. The next prime is 21003220319. The reversal of 21003220305 is 50302230012.

It can be written as a sum of positive squares in 2 ways, for example, as 12280407489 + 8722812816 = 110817^2 + 93396^2 .

It is not a de Polignac number, because 21003220305 - 2³ = 21003220297 is a prime.

It is a super-2 number, since 2×21003220305² (a number of 21 digits) contains 22 as substring.

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 11 ways as a sum of consecutive naturals, for example, 233369070 + ... + 233369159.

It is an arithmetic number, because the mean of its divisors is an integer number (3033798495).

Almost surely, 2^21003220305 is an apocalyptic number.

It is an amenable number.

21003220305 is a deficient number, since it is larger than the sum of its proper divisors (15402361635).

21003220305 is a wasteful number, since it uses less digits than its factorization.

21003220305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 466738240 (or 466738237 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 18.

Adding to 21003220305 its reverse (50302230012), we get a palindrome (71305450317).

The spelling of 21003220305 in words is "twenty-one billion, three million, two hundred twenty thousand, three hundred five".