21452321 has 4 divisors (see below), whose sum is σ = 23402544. Its totient is φ = 19502100.

The previous prime is 21452309. The next prime is 21452339. The reversal of 21452321 is 12325412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21452321 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 21452293 and 21452302.

It is not an unprimeable number, because it can be changed into a prime (21452021) 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 3 ways as a sum of consecutive naturals, for example, 975095 + ... + 975116.

It is an arithmetic number, because the mean of its divisors is an integer number (5850636).

Almost surely, 2^21452321 is an apocalyptic number.

It is an amenable number.

21452321 is a deficient number, since it is larger than the sum of its proper divisors (1950223).

21452321 is a wasteful number, since it uses less digits than its factorization.

21452321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1950222.

The product of its digits is 480, while the sum is 20.

The square root of 21452321 is about 4631.6650353841. The cubic root of 21452321 is about 277.8591880434.

Adding to 21452321 its reverse (12325412), we get a palindrome (33777733).

The spelling of 21452321 in words is "twenty-one million, four hundred fifty-two thousand, three hundred twenty-one".