21784725530 has 16 divisors (see below), whose sum is σ = 39244434120. Its totient is φ = 8706795072.

The previous prime is 21784725493. The next prime is 21784725581. The reversal of 21784725530 is 3552748712.

21784725530 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 20978335921 + 806389609 = 144839^2 + 28397^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 873989 + ... + 898568.

Almost surely, 2^21784725530 is an apocalyptic number.

21784725530 is a deficient number, since it is larger than the sum of its proper divisors (17459708590).

21784725530 is a wasteful number, since it uses less digits than its factorization.

21784725530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1773793.

The product of its (nonzero) digits is 470400, while the sum is 44.

The spelling of 21784725530 in words is "twenty-one billion, seven hundred eighty-four million, seven hundred twenty-five thousand, five hundred thirty".