21243682 has 8 divisors (see below), whose sum is σ = 31889052. Its totient is φ = 10614000.

The previous prime is 21243637. The next prime is 21243683. The reversal of 21243682 is 28634212.

It can be written as a sum of positive squares in 2 ways, for example, as 19280881 + 1962801 = 4391^2 + 1401^2 .

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 21243682.

It is not an unprimeable number, because it can be changed into a prime (21243683) 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, 432 + ... + 6532.

Almost surely, 2^21243682 is an apocalyptic number.

21243682 is a deficient number, since it is larger than the sum of its proper divisors (10645370).

21243682 is a wasteful number, since it uses less digits than its factorization.

21243682 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7844.

The product of its digits is 4608, while the sum is 28.

The square root of 21243682 is about 4609.0868943859. The cubic root of 21243682 is about 276.9554594808.

Adding to 21243682 its reverse (28634212), we get a palindrome (49877894).

The spelling of 21243682 in words is "twenty-one million, two hundred forty-three thousand, six hundred eighty-two".