21304533 has 8 divisors (see below), whose sum is σ = 29322496. Its totient is φ = 13744800.

The previous prime is 21304511. The next prime is 21304537. The reversal of 21304533 is 33540312.

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

It is not a de Polignac number, because 21304533 - 2⁵ = 21304501 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 (21304537) 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, 114448 + ... + 114633.

It is an arithmetic number, because the mean of its divisors is an integer number (3665312).

Almost surely, 2^21304533 is an apocalyptic number.

It is an amenable number.

21304533 is a deficient number, since it is larger than the sum of its proper divisors (8017963).

21304533 is a wasteful number, since it uses less digits than its factorization.

21304533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229115.

The product of its (nonzero) digits is 1080, while the sum is 21.

The square root of 21304533 is about 4615.6833730229. The cubic root of 21304533 is about 277.2196470606.

Adding to 21304533 its reverse (33540312), we get a palindrome (54844845).

The spelling of 21304533 in words is "twenty-one million, three hundred four thousand, five hundred thirty-three".