21318847 has 16 divisors (see below), whose sum is σ = 23869440. Its totient is φ = 18878400.

The previous prime is 21318839. The next prime is 21318859. The reversal of 21318847 is 74881312.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21318847 - 2³ = 21318839 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21318877) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 111522 + ... + 111712.

It is an arithmetic number, because the mean of its divisors is an integer number (1491840).

Almost surely, 2^21318847 is an apocalyptic number.

21318847 is a deficient number, since it is larger than the sum of its proper divisors (2550593).

21318847 is a wasteful number, since it uses less digits than its factorization.

21318847 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 414.

The product of its digits is 10752, while the sum is 34.

The square root of 21318847 is about 4617.2336956234. The cubic root of 21318847 is about 277.2817188846.

The spelling of 21318847 in words is "twenty-one million, three hundred eighteen thousand, eight hundred forty-seven".