21118424 has 16 divisors (see below), whose sum is σ = 41681400. Its totient is φ = 10003392.

The previous prime is 21118411. The next prime is 21118441. The reversal of 21118424 is 42481112.

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 21118424.

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, 69317 + ... + 69620.

Almost surely, 2^21118424 is an apocalyptic number.

It is an amenable number.

21118424 is a deficient number, since it is larger than the sum of its proper divisors (20562976).

21118424 is a wasteful number, since it uses less digits than its factorization.

21118424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138962 (or 138958 counting only the distinct ones).

The product of its digits is 512, while the sum is 23.

The square root of 21118424 is about 4595.4786475404. The cubic root of 21118424 is about 276.4100535073.

Adding to 21118424 its reverse (42481112), we get a palindrome (63599536).

The spelling of 21118424 in words is "twenty-one million, one hundred eighteen thousand, four hundred twenty-four".