21045530 has 24 divisors (see below), whose sum is σ = 41641236. Its totient is φ = 7652480.

The previous prime is 21045527. The next prime is 21045539. The reversal of 21045530 is 3554012.

It can be written as a sum of positive squares in 2 ways, for example, as 20043529 + 1002001 = 4477^2 + 1001^2 .

It is not an unprimeable number, because it can be changed into a prime (21045539) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7487 + ... + 9906.

Almost surely, 2^21045530 is an apocalyptic number.

21045530 is a deficient number, since it is larger than the sum of its proper divisors (20595706).

21045530 is a wasteful number, since it uses less digits than its factorization.

21045530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17422 (or 17411 counting only the distinct ones).

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

The square root of 21045530 is about 4587.5407355140. The cubic root of 21045530 is about 276.0916607271.

Adding to 21045530 its reverse (3554012), we get a palindrome (24599542).

The spelling of 21045530 in words is "twenty-one million, forty-five thousand, five hundred thirty".