21641324 has 6 divisors (see below), whose sum is σ = 37872324. Its totient is φ = 10820660.

The previous prime is 21641311. The next prime is 21641353. The reversal of 21641324 is 42314612.

It is a self number, because there is not a number n which added to its sum of digits gives 21641324.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 2705162 + ... + 2705169.

It is an arithmetic number, because the mean of its divisors is an integer number (6312054).

Almost surely, 2^21641324 is an apocalyptic number.

It is an amenable number.

21641324 is a deficient number, since it is larger than the sum of its proper divisors (16231000).

21641324 is a wasteful number, since it uses less digits than its factorization.

21641324 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5410335 (or 5410333 counting only the distinct ones).

The product of its digits is 1152, while the sum is 23.

The square root of 21641324 is about 4652.0236456837. The cubic root of 21641324 is about 278.6728178197.

Adding to 21641324 its reverse (42314612), we get a palindrome (63955936).

The spelling of 21641324 in words is "twenty-one million, six hundred forty-one thousand, three hundred twenty-four".