21326447 has 4 divisors (see below), whose sum is σ = 21566160. Its totient is φ = 21086736.

The previous prime is 21326441. The next prime is 21326477. The reversal of 21326447 is 74462312.

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 21326447 - 2¹⁴ = 21310063 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 (21326441) 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, 119723 + ... + 119900.

It is an arithmetic number, because the mean of its divisors is an integer number (5391540).

Almost surely, 2^21326447 is an apocalyptic number.

21326447 is a deficient number, since it is larger than the sum of its proper divisors (239713).

21326447 is an equidigital number, since it uses as much as digits as its factorization.

21326447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 239712.

The product of its digits is 8064, while the sum is 29.

The square root of 21326447 is about 4618.0566258980. The cubic root of 21326447 is about 277.3146645484.

Adding to 21326447 its reverse (74462312), we get a palindrome (95788759).

The spelling of 21326447 in words is "twenty-one million, three hundred twenty-six thousand, four hundred forty-seven".