21453321 has 8 divisors (see below), whose sum is σ = 28776384. Its totient is φ = 14216240.

The previous prime is 21453307. The next prime is 21453323. The reversal of 21453321 is 12335412.

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 21453321 - 2⁷ = 21453193 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21453323) 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, 20910 + ... + 21911.

It is an arithmetic number, because the mean of its divisors is an integer number (3597048).

Almost surely, 2^21453321 is an apocalyptic number.

It is an amenable number.

21453321 is a deficient number, since it is larger than the sum of its proper divisors (7323063).

21453321 is a wasteful number, since it uses less digits than its factorization.

21453321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42991.

The product of its digits is 720, while the sum is 21.

The square root of 21453321 is about 4631.7729866650. The cubic root of 21453321 is about 277.8635054452.

Adding to 21453321 its reverse (12335412), we get a palindrome (33788733).

It can be divided in two parts, 214 and 53321, that added together give a palindrome (53535).

The spelling of 21453321 in words is "twenty-one million, four hundred fifty-three thousand, three hundred twenty-one".