21318473 has 8 divisors (see below), whose sum is σ = 23414400. Its totient is φ = 19248880.

The previous prime is 21318469. The next prime is 21318481. The reversal of 21318473 is 37481312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21318473 - 2² = 21318469 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21318403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4865 + ... + 8142.

It is an arithmetic number, because the mean of its divisors is an integer number (2926800).

Almost surely, 2^21318473 is an apocalyptic number.

It is an amenable number.

21318473 is a deficient number, since it is larger than the sum of its proper divisors (2095927).

21318473 is a wasteful number, since it uses less digits than its factorization.

21318473 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13167.

The product of its digits is 4032, while the sum is 29.

The square root of 21318473 is about 4617.1931950049. The cubic root of 21318473 is about 277.2800974090.

Adding to 21318473 its reverse (37481312), we get a palindrome (58799785).

The spelling of 21318473 in words is "twenty-one million, three hundred eighteen thousand, four hundred seventy-three".