21208252 has 48 divisors (see below), whose sum is σ = 41887552. Its totient is φ = 9331200.

The previous prime is 21208183. The next prime is 21208259. The reversal of 21208252 is 25280212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21208259) by changing a digit.

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 in 15 ways as a sum of consecutive naturals, for example, 140377 + ... + 140527.

Almost surely, 2^21208252 is an apocalyptic number.

It is an amenable number.

21208252 is a deficient number, since it is larger than the sum of its proper divisors (20679300).

21208252 is a wasteful number, since it uses less digits than its factorization.

21208252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 278 (or 276 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 22.

The square root of 21208252 is about 4605.2417960407. The cubic root of 21208252 is about 276.8014059592.

Adding to 21208252 its reverse (25280212), we get a palindrome (46488464).

The spelling of 21208252 in words is "twenty-one million, two hundred eight thousand, two hundred fifty-two".