21116584 has 16 divisors (see below), whose sum is σ = 41922900. Its totient is φ = 9937152.

The previous prime is 21116561. The next prime is 21116587. The reversal of 21116584 is 48561112.

It can be written as a sum of positive squares in 2 ways, for example, as 20160100 + 956484 = 4490^2 + 978^2 .

It is not an unprimeable number, because it can be changed into a prime (21116587) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77499 + ... + 77770.

Almost surely, 2^21116584 is an apocalyptic number.

It is an amenable number.

21116584 is a deficient number, since it is larger than the sum of its proper divisors (20806316).

21116584 is a wasteful number, since it uses less digits than its factorization.

21116584 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155292 (or 155288 counting only the distinct ones).

The product of its digits is 1920, while the sum is 28.

The square root of 21116584 is about 4595.2784464056. The cubic root of 21116584 is about 276.4020256155.

Adding to 21116584 its reverse (48561112), we get a palindrome (69677696).

The spelling of 21116584 in words is "twenty-one million, one hundred sixteen thousand, five hundred eighty-four".