21440333 has 4 divisors (see below), whose sum is σ = 21594720. Its totient is φ = 21285948.

The previous prime is 21440317. The next prime is 21440351. The reversal of 21440333 is 33304412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21440333 - 2⁴ = 21440317 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21440233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 76985 + ... + 77262.

It is an arithmetic number, because the mean of its divisors is an integer number (5398680).

Almost surely, 2^21440333 is an apocalyptic number.

It is an amenable number.

21440333 is a deficient number, since it is larger than the sum of its proper divisors (154387).

21440333 is a wasteful number, since it uses less digits than its factorization.

21440333 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154386.

The product of its (nonzero) digits is 864, while the sum is 20.

The square root of 21440333 is about 4630.3707194997. The cubic root of 21440333 is about 277.8074205818.

Adding to 21440333 its reverse (33304412), we get a palindrome (54744745).

The spelling of 21440333 in words is "twenty-one million, four hundred forty thousand, three hundred thirty-three".