21043321 has 8 divisors (see below), whose sum is σ = 23647680. Its totient is φ = 18579792.

The previous prime is 21043313. The next prime is 21043339. The reversal of 21043321 is 12334012.

It is a happy number.

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 21043321 - 2³ = 21043313 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21043295 and 21043304.

It is not an unprimeable number, because it can be changed into a prime (21043301) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34891 + ... + 35488.

It is an arithmetic number, because the mean of its divisors is an integer number (2955960).

Almost surely, 2^21043321 is an apocalyptic number.

It is an amenable number.

21043321 is a deficient number, since it is larger than the sum of its proper divisors (2604359).

21043321 is a wasteful number, since it uses less digits than its factorization.

21043321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70415.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21043321 is about 4587.2999683910. The cubic root of 21043321 is about 276.0820005947.

Adding to 21043321 its reverse (12334012), we get a palindrome (33377333).

The spelling of 21043321 in words is "twenty-one million, forty-three thousand, three hundred twenty-one".