21530522 has 16 divisors (see below), whose sum is σ = 35721672. Its totient is φ = 9668160.

The previous prime is 21530513. The next prime is 21530527. The reversal of 21530522 is 22503512.

It can be written as a sum of positive squares in 4 ways, for example, as 19545241 + 1985281 = 4421^2 + 1409^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21530494 and 21530503.

It is not an unprimeable number, because it can be changed into a prime (21530527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10229 + ... + 12152.

Almost surely, 2^21530522 is an apocalyptic number.

21530522 is a deficient number, since it is larger than the sum of its proper divisors (14191150).

21530522 is a wasteful number, since it uses less digits than its factorization.

21530522 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22433.

The product of its (nonzero) digits is 600, while the sum is 20.

The square root of 21530522 is about 4640.0993523846. The cubic root of 21530522 is about 278.1964090007.

The spelling of 21530522 in words is "twenty-one million, five hundred thirty thousand, five hundred twenty-two".