21042120530 has 16 divisors (see below), whose sum is σ = 37893645720. Its totient is φ = 8412886272.

The previous prime is 21042120529. The next prime is 21042120581. The reversal of 21042120530 is 3502124012.

21042120530 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 15026101561 + 6016018969 = 122581^2 + 77563^2 .

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 7 ways as a sum of consecutive naturals, for example, 472889 + ... + 515468.

Almost surely, 2^21042120530 is an apocalyptic number.

21042120530 is a deficient number, since it is larger than the sum of its proper divisors (16851525190).

21042120530 is a wasteful number, since it uses less digits than its factorization.

21042120530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 990493.

The product of its (nonzero) digits is 480, while the sum is 20.

Adding to 21042120530 its reverse (3502124012), we get a palindrome (24544244542).

The spelling of 21042120530 in words is "twenty-one billion, forty-two million, one hundred twenty thousand, five hundred thirty".