21206433 has 8 divisors (see below), whose sum is σ = 28311808. Its totient is φ = 14119344.

The previous prime is 21206407. The next prime is 21206441. The reversal of 21206433 is 33460212.

It is a happy number.

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

It is not a de Polignac number, because 21206433 - 2⁵ = 21206401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21206443) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 1585 + ... + 6702.

It is an arithmetic number, because the mean of its divisors is an integer number (3538976).

Almost surely, 2^21206433 is an apocalyptic number.

It is an amenable number.

21206433 is a deficient number, since it is larger than the sum of its proper divisors (7105375).

21206433 is an equidigital number, since it uses as much as digits as its factorization.

21206433 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9143.

The product of its (nonzero) digits is 864, while the sum is 21.

The square root of 21206433 is about 4605.0442994612. The cubic root of 21206433 is about 276.7934921190.

Adding to 21206433 its reverse (33460212), we get a palindrome (54666645).

The spelling of 21206433 in words is "twenty-one million, two hundred six thousand, four hundred thirty-three".