21330306 has 12 divisors (see below), whose sum is σ = 46215702. Its totient is φ = 7110096.

The previous prime is 21330299. The next prime is 21330311. The reversal of 21330306 is 60303312.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 19053225 + 2277081 = 4365^2 + 1509^2 .

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 1185017 = 21330306 / (2 + 1 + 3 + 3 + 0 + 3 + 0 + 6).

It is a plaindrome in base 13.

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 5 ways as a sum of consecutive naturals, for example, 592491 + ... + 592526.

Almost surely, 2^21330306 is an apocalyptic number.

21330306 is an abundant number, since it is smaller than the sum of its proper divisors (24885396).

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

21330306 is a wasteful number, since it uses less digits than its factorization.

21330306 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1185025 (or 1185022 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 18.

The square root of 21330306 is about 4618.4744234433. The cubic root of 21330306 is about 277.3313901465.

Adding to 21330306 its reverse (60303312), we get a palindrome (81633618).

The spelling of 21330306 in words is "twenty-one million, three hundred thirty thousand, three hundred six".