21242584 has 16 divisors (see below), whose sum is σ = 43450920. Its totient is φ = 9655680.

The previous prime is 21242569. The next prime is 21242591. The reversal of 21242584 is 48524212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 120609 + ... + 120784.

Almost surely, 2^21242584 is an apocalyptic number.

It is an amenable number.

21242584 is an abundant number, since it is smaller than the sum of its proper divisors (22208336).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21242584 is a wasteful number, since it uses less digits than its factorization.

21242584 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241410 (or 241406 counting only the distinct ones).

The product of its digits is 5120, while the sum is 28.

The square root of 21242584 is about 4608.9677803170. The cubic root of 21242584 is about 276.9506878294.

Adding to 21242584 its reverse (48524212), we get a palindrome (69766796).

The spelling of 21242584 in words is "twenty-one million, two hundred forty-two thousand, five hundred eighty-four".