21433385 has 4 divisors (see below), whose sum is σ = 25720068. Its totient is φ = 17146704.

The previous prime is 21433361. The next prime is 21433417. The reversal of 21433385 is 58333412.

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 5216656 + 16216729 = 2284^2 + 4027^2 .

It is a cyclic number.

It is not a de Polignac number, because 21433385 - 2⁸ = 21433129 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2143334 + ... + 2143343.

It is an arithmetic number, because the mean of its divisors is an integer number (6430017).

Almost surely, 2^21433385 is an apocalyptic number.

It is an amenable number.

21433385 is a deficient number, since it is larger than the sum of its proper divisors (4286683).

21433385 is an equidigital number, since it uses as much as digits as its factorization.

21433385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4286682.

The product of its digits is 8640, while the sum is 29.

The square root of 21433385 is about 4629.6203948056. The cubic root of 21433385 is about 277.7774083847. Note that the first 3 decimals are identical.

Adding to 21433385 its reverse (58333412), we get a palindrome (79766797).

The spelling of 21433385 in words is "twenty-one million, four hundred thirty-three thousand, three hundred eighty-five".