21530452 has 6 divisors (see below), whose sum is σ = 37678298. Its totient is φ = 10765224.

The previous prime is 21530447. The next prime is 21530459. The reversal of 21530452 is 25403512.

It can be written as a sum of positive squares in only one way, i.e., 12068676 + 9461776 = 3474^2 + 3076^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21530459) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2691303 + ... + 2691310.

Almost surely, 2^21530452 is an apocalyptic number.

It is an amenable number.

21530452 is a deficient number, since it is larger than the sum of its proper divisors (16147846).

21530452 is a wasteful number, since it uses less digits than its factorization.

21530452 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5382617 (or 5382615 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 22.

The square root of 21530452 is about 4640.0918094365. The cubic root of 21530452 is about 278.1961075098.

Adding to 21530452 its reverse (25403512), we get a palindrome (46933964).

The spelling of 21530452 in words is "twenty-one million, five hundred thirty thousand, four hundred fifty-two".