21318382 has 4 divisors (see below), whose sum is σ = 31977576. Its totient is φ = 10659190.

The previous prime is 21318379. The next prime is 21318397. The reversal of 21318382 is 28381312.

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

It is a super-2 number, since 2×21318382² = 908946822195848, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21318382.

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, 5329594 + ... + 5329597.

It is an arithmetic number, because the mean of its divisors is an integer number (7994394).

Almost surely, 2^21318382 is an apocalyptic number.

21318382 is a deficient number, since it is larger than the sum of its proper divisors (10659194).

21318382 is a wasteful number, since it uses less digits than its factorization.

21318382 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10659193.

The product of its digits is 2304, while the sum is 28.

The square root of 21318382 is about 4617.1833405227. The cubic root of 21318382 is about 277.2797028760.

Adding to 21318382 its reverse (28381312), we get a palindrome (49699694).

The spelling of 21318382 in words is "twenty-one million, three hundred eighteen thousand, three hundred eighty-two".