21208246 has 4 divisors (see below), whose sum is σ = 31812372. Its totient is φ = 10604122.

The previous prime is 21208183. The next prime is 21208259. The reversal of 21208246 is 64280212.

It is a happy number.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21208246.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5302060 + ... + 5302063.

It is an arithmetic number, because the mean of its divisors is an integer number (7953093).

Almost surely, 2^21208246 is an apocalyptic number.

21208246 is a deficient number, since it is larger than the sum of its proper divisors (10604126).

21208246 is a wasteful number, since it uses less digits than its factorization.

21208246 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10604125.

The product of its (nonzero) digits is 1536, while the sum is 25.

The square root of 21208246 is about 4605.2411446090. The cubic root of 21208246 is about 276.8013798560.

Adding to 21208246 its reverse (64280212), we get a palindrome (85488458).

The spelling of 21208246 in words is "twenty-one million, two hundred eight thousand, two hundred forty-six".