21322447 has 4 divisors (see below), whose sum is σ = 21433120. Its totient is φ = 21211776.

The previous prime is 21322439. The next prime is 21322463. The reversal of 21322447 is 74422312.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21322447 - 2³ = 21322439 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21322417) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55047 + ... + 55432.

It is an arithmetic number, because the mean of its divisors is an integer number (5358280).

Almost surely, 2^21322447 is an apocalyptic number.

21322447 is a deficient number, since it is larger than the sum of its proper divisors (110673).

21322447 is a wasteful number, since it uses less digits than its factorization.

21322447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110672.

The product of its digits is 2688, while the sum is 25.

The square root of 21322447 is about 4617.6235229824. The cubic root of 21322447 is about 277.2973257012.

Adding to 21322447 its reverse (74422312), we get a palindrome (95744759).

The spelling of 21322447 in words is "twenty-one million, three hundred twenty-two thousand, four hundred forty-seven".