21232003505 has 4 divisors (see below), whose sum is σ = 25478404212. Its totient is φ = 16985602800.

The previous prime is 21232003483. The next prime is 21232003531. The reversal of 21232003505 is 50530023212.

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 15827401249 + 5404602256 = 125807^2 + 73516^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21232003505 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 (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2123200346 + ... + 2123200355.

It is an arithmetic number, because the mean of its divisors is an integer number (6369601053).

Almost surely, 2^21232003505 is an apocalyptic number.

It is an amenable number.

21232003505 is a deficient number, since it is larger than the sum of its proper divisors (4246400707).

21232003505 is an equidigital number, since it uses as much as digits as its factorization.

21232003505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4246400706.

The product of its (nonzero) digits is 1800, while the sum is 23.

Adding to 21232003505 its reverse (50530023212), we get a palindrome (71762026717).

The spelling of 21232003505 in words is "twenty-one billion, two hundred thirty-two million, three thousand, five hundred five".