21118582 has 4 divisors (see below), whose sum is σ = 31677876. Its totient is φ = 10559290.

The previous prime is 21118579. The next prime is 21118613. The reversal of 21118582 is 28581112.

It is a semiprime because it is the product of two primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21118582.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5279644 + ... + 5279647.

It is an arithmetic number, because the mean of its divisors is an integer number (7919469).

Almost surely, 2^21118582 is an apocalyptic number.

21118582 is a deficient number, since it is larger than the sum of its proper divisors (10559294).

21118582 is a wasteful number, since it uses less digits than its factorization.

21118582 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10559293.

The product of its digits is 1280, while the sum is 28.

The square root of 21118582 is about 4595.4958383182. The cubic root of 21118582 is about 276.4107428372.

Adding to 21118582 its reverse (28581112), we get a palindrome (49699694).

The spelling of 21118582 in words is "twenty-one million, one hundred eighteen thousand, five hundred eighty-two".