21328266 has 8 divisors (see below), whose sum is σ = 42656544. Its totient is φ = 7109420.

The previous prime is 21328247. The next prime is 21328273. The reversal of 21328266 is 66282312.

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

21328266 is an admirable number.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1777350 + ... + 1777361.

It is an arithmetic number, because the mean of its divisors is an integer number (5332068).

Almost surely, 2^21328266 is an apocalyptic number.

21328266 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.

21328266 is a wasteful number, since it uses less digits than its factorization.

21328266 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3554716.

The product of its digits is 6912, while the sum is 30.

The square root of 21328266 is about 4618.2535660139. The cubic root of 21328266 is about 277.3225486720.

The spelling of 21328266 in words is "twenty-one million, three hundred twenty-eight thousand, two hundred sixty-six".