21540433 has 8 divisors (see below), whose sum is σ = 23013920. Its totient is φ = 20100960.

The previous prime is 21540383. The next prime is 21540437. The reversal of 21540433 is 33404512.

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

It is a cyclic number.

It is not a de Polignac number, because 21540433 - 2¹⁷ = 21409361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21540437) 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, 7188 + ... + 9733.

It is an arithmetic number, because the mean of its divisors is an integer number (2876740).

Almost surely, 2^21540433 is an apocalyptic number.

It is an amenable number.

21540433 is a deficient number, since it is larger than the sum of its proper divisors (1473487).

21540433 is a wasteful number, since it uses less digits than its factorization.

21540433 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17007.

The product of its (nonzero) digits is 1440, while the sum is 22.

The square root of 21540433 is about 4641.1672023318. The cubic root of 21540433 is about 278.2390892114.

Adding to 21540433 its reverse (33404512), we get a palindrome (54944945).

The spelling of 21540433 in words is "twenty-one million, five hundred forty thousand, four hundred thirty-three".