21864227 has 16 divisors (see below), whose sum is σ = 28864512. Its totient is φ = 16033920.

The previous prime is 21864217. The next prime is 21864229. The reversal of 21864227 is 72246812.

It is not a de Polignac number, because 21864227 - 2²⁰ = 20815651 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21864193 and 21864202.

It is not an unprimeable number, because it can be changed into a prime (21864229) 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, 7043 + ... + 9660.

It is an arithmetic number, because the mean of its divisors is an integer number (1804032).

Almost surely, 2^21864227 is an apocalyptic number.

21864227 is a deficient number, since it is larger than the sum of its proper divisors (7000285).

21864227 is a wasteful number, since it uses less digits than its factorization.

21864227 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16738.

The product of its digits is 10752, while the sum is 32.

The square root of 21864227 is about 4675.9199094937. The cubic root of 21864227 is about 279.6263169874.

The spelling of 21864227 in words is "twenty-one million, eight hundred sixty-four thousand, two hundred twenty-seven".