21406333 has 4 divisors (see below), whose sum is σ = 23052988. Its totient is φ = 19759680.

The previous prime is 21406279. The next prime is 21406339. The reversal of 21406333 is 33360412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7064964 + 14341369 = 2658^2 + 3787^2 .

It is a cyclic number.

It is not a de Polignac number, because 21406333 - 2¹³ = 21398141 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21406339) 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, 823308 + ... + 823333.

It is an arithmetic number, because the mean of its divisors is an integer number (5763247).

Almost surely, 2^21406333 is an apocalyptic number.

It is an amenable number.

21406333 is a deficient number, since it is larger than the sum of its proper divisors (1646655).

21406333 is a wasteful number, since it uses less digits than its factorization.

21406333 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1646654.

The product of its (nonzero) digits is 1296, while the sum is 22.

The square root of 21406333 is about 4626.6978505193. The cubic root of 21406333 is about 277.6604942326.

Adding to 21406333 its reverse (33360412), we get a palindrome (54766745).

The spelling of 21406333 in words is "twenty-one million, four hundred six thousand, three hundred thirty-three".