21068305 has 8 divisors (see below), whose sum is σ = 25587072. Its totient is φ = 16651248.

The previous prime is 21068291. The next prime is 21068309. The reversal of 21068305 is 50386012.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21068305 - 2¹¹ = 21066257 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21068305.

It is not an unprimeable number, because it can be changed into a prime (21068309) 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, 24969 + ... + 25798.

It is an arithmetic number, because the mean of its divisors is an integer number (3198384).

Almost surely, 2^21068305 is an apocalyptic number.

It is an amenable number.

21068305 is a deficient number, since it is larger than the sum of its proper divisors (4518767).

21068305 is an equidigital number, since it uses as much as digits as its factorization.

21068305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50855.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 21068305 is about 4590.0223311004. The cubic root of 21068305 is about 276.1912182213.

Multiplying 21068305 by its sum of digits (25), we get a palindrome (526707625).

The spelling of 21068305 in words is "twenty-one million, sixty-eight thousand, three hundred five".