21838686 has 8 divisors (see below), whose sum is σ = 43677384. Its totient is φ = 7279560.

The previous prime is 21838679. The next prime is 21838723. The reversal of 21838686 is 68683812.

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

21838686 is an admirable number.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1819885 + ... + 1819896.

It is an arithmetic number, because the mean of its divisors is an integer number (5459673).

Almost surely, 2^21838686 is an apocalyptic number.

21838686 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21838686 is a wasteful number, since it uses less digits than its factorization.

21838686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3639786.

The product of its digits is 110592, while the sum is 42.

The square root of 21838686 is about 4673.1879910827. The cubic root of 21838686 is about 279.5173914420.

The spelling of 21838686 in words is "twenty-one million, eight hundred thirty-eight thousand, six hundred eighty-six".