21318845 has 8 divisors (see below), whose sum is σ = 26274264. Its totient is φ = 16593984.

The previous prime is 21318839. The next prime is 21318859. The reversal of 21318845 is 54881312.

It can be written as a sum of positive squares in 4 ways, for example, as 5866084 + 15452761 = 2422^2 + 3931^2 .

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 21318845 - 2¹² = 21314749 is a prime.

It is a Duffinian number.

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 in 7 ways as a sum of consecutive naturals, for example, 57434 + ... + 57803.

It is an arithmetic number, because the mean of its divisors is an integer number (3284283).

Almost surely, 2^21318845 is an apocalyptic number.

It is an amenable number.

21318845 is a deficient number, since it is larger than the sum of its proper divisors (4955419).

21318845 is a wasteful number, since it uses less digits than its factorization.

21318845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115279.

The product of its digits is 7680, while the sum is 32.

The square root of 21318845 is about 4617.2334790435. The cubic root of 21318845 is about 277.2817102136.

The spelling of 21318845 in words is "twenty-one million, three hundred eighteen thousand, eight hundred forty-five".