21208672 has 12 divisors (see below), whose sum is σ = 41754636. Its totient is φ = 10604320.

The previous prime is 21208667. The next prime is 21208697. The reversal of 21208672 is 27680212.

It is a self number, because there is not a number n which added to its sum of digits gives 21208672.

It is a congruent number.

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, 331354 + ... + 331417.

It is an arithmetic number, because the mean of its divisors is an integer number (3479553).

Almost surely, 2^21208672 is an apocalyptic number.

It is an amenable number.

21208672 is a deficient number, since it is larger than the sum of its proper divisors (20545964).

21208672 is an equidigital number, since it uses as much as digits as its factorization.

21208672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 662781 (or 662773 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 21208672 is about 4605.2873960264. The cubic root of 21208672 is about 276.8032331697.

Adding to 21208672 its reverse (27680212), we get a palindrome (48888884).

The spelling of 21208672 in words is "twenty-one million, two hundred eight thousand, six hundred seventy-two".