21328386 has 8 divisors (see below), whose sum is σ = 42656784. Its totient is φ = 7109460.

The previous prime is 21328381. The next prime is 21328399. The reversal of 21328386 is 68382312.

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

21328386 is an admirable number.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21328381) 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, 1777360 + ... + 1777371.

It is an arithmetic number, because the mean of its divisors is an integer number (5332098).

Almost surely, 2^21328386 is an apocalyptic number.

21328386 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.

21328386 is a wasteful number, since it uses less digits than its factorization.

21328386 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3554736.

The product of its digits is 13824, while the sum is 33.

The square root of 21328386 is about 4618.2665579198. The cubic root of 21328386 is about 277.3230687743.

The spelling of 21328386 in words is "twenty-one million, three hundred twenty-eight thousand, three hundred eighty-six".