21318838 has 8 divisors (see below), whose sum is σ = 33368688. Its totient is φ = 10195944.

The previous prime is 21318821. The next prime is 21318839. The reversal of 21318838 is 83881312.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21318839) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 231681 + ... + 231772.

It is an arithmetic number, because the mean of its divisors is an integer number (4171086).

Almost surely, 2^21318838 is an apocalyptic number.

21318838 is a deficient number, since it is larger than the sum of its proper divisors (12049850).

21318838 is a wasteful number, since it uses less digits than its factorization.

21318838 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 463478.

The product of its digits is 9216, while the sum is 34.

The square root of 21318838 is about 4617.2327210137. The cubic root of 21318838 is about 277.2816798653.

The spelling of 21318838 in words is "twenty-one million, three hundred eighteen thousand, eight hundred thirty-eight".