21864238 has 16 divisors (see below), whose sum is σ = 36933120. Its totient is φ = 9617400.

The previous prime is 21864229. The next prime is 21864239. The reversal of 21864238 is 83246812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21864239) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15348 + ... + 16711.

It is an arithmetic number, because the mean of its divisors is an integer number (2308320).

Almost surely, 2^21864238 is an apocalyptic number.

21864238 is a deficient number, since it is larger than the sum of its proper divisors (15068882).

21864238 is a wasteful number, since it uses less digits than its factorization.

21864238 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32103.

The product of its digits is 18432, while the sum is 34.

The square root of 21864238 is about 4675.9210857327. The cubic root of 21864238 is about 279.6263638811.

The spelling of 21864238 in words is "twenty-one million, eight hundred sixty-four thousand, two hundred thirty-eight".