21321242 has 8 divisors (see below), whose sum is σ = 33013632. Its totient is φ = 10316700.

The previous prime is 21321217. The next prime is 21321263. The reversal of 21321242 is 24212312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21321242.

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 in 3 ways as a sum of consecutive naturals, for example, 171884 + ... + 172007.

It is an arithmetic number, because the mean of its divisors is an integer number (4126704).

Almost surely, 2^21321242 is an apocalyptic number.

21321242 is a deficient number, since it is larger than the sum of its proper divisors (11692390).

21321242 is a wasteful number, since it uses less digits than its factorization.

21321242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 343924.

The product of its digits is 192, while the sum is 17.

The square root of 21321242 is about 4617.4930427668. The cubic root of 21321242 is about 277.2921019485.

Adding to 21321242 its reverse (24212312), we get a palindrome (45533554).

The spelling of 21321242 in words is "twenty-one million, three hundred twenty-one thousand, two hundred forty-two".