21571252 has 12 divisors (see below), whose sum is σ = 37791936. Its totient is φ = 10773560.

The previous prime is 21571243. The next prime is 21571267. The reversal of 21571252 is 25217512.

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 in 3 ways as a sum of consecutive naturals, for example, 1893 + ... + 6835.

It is an arithmetic number, because the mean of its divisors is an integer number (3149328).

Almost surely, 2^21571252 is an apocalyptic number.

It is an amenable number.

21571252 is a deficient number, since it is larger than the sum of its proper divisors (16220684).

21571252 is a wasteful number, since it uses less digits than its factorization.

21571252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6038 (or 6036 counting only the distinct ones).

The product of its digits is 1400, while the sum is 25.

The square root of 21571252 is about 4644.4861933264. The cubic root of 21571252 is about 278.3717229449.

Adding to 21571252 its reverse (25217512), we get a palindrome (46788764).

The spelling of 21571252 in words is "twenty-one million, five hundred seventy-one thousand, two hundred fifty-two".