21530416 has 10 divisors (see below), whose sum is σ = 41715212. Its totient is φ = 10765200.

The previous prime is 21530413. The next prime is 21530447. The reversal of 21530416 is 61403512.

It is not an unprimeable number, because it can be changed into a prime (21530413) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 672810 + ... + 672841.

Almost surely, 2^21530416 is an apocalyptic number.

It is an amenable number.

21530416 is a deficient number, since it is larger than the sum of its proper divisors (20184796).

21530416 is a wasteful number, since it uses less digits than its factorization.

21530416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1345659 (or 1345653 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 21530416 is about 4640.0879302013. The cubic root of 21530416 is about 278.1959524571.

Adding to 21530416 its reverse (61403512), we get a palindrome (82933928).

The spelling of 21530416 in words is "twenty-one million, five hundred thirty thousand, four hundred sixteen".