21445252 has 12 divisors (see below), whose sum is σ = 37596636. Its totient is φ = 10703360.

The previous prime is 21445247. The next prime is 21445327. The reversal of 21445252 is 25254412.

It can be written as a sum of positive squares in 2 ways, for example, as 18541636 + 2903616 = 4306^2 + 1704^2 .

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, 2149 + ... + 6892.

It is an arithmetic number, because the mean of its divisors is an integer number (3133053).

Almost surely, 2^21445252 is an apocalyptic number.

It is an amenable number.

21445252 is a deficient number, since it is larger than the sum of its proper divisors (16151384).

21445252 is a wasteful number, since it uses less digits than its factorization.

21445252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9638 (or 9636 counting only the distinct ones).

The product of its digits is 3200, while the sum is 25.

The square root of 21445252 is about 4630.9018560103. The cubic root of 21445252 is about 277.8286645026.

Adding to 21445252 its reverse (25254412), we get a palindrome (46699664).

It can be divided in two parts, 2144 and 5252, that added together give a square (7396 = 86²).

The spelling of 21445252 in words is "twenty-one million, four hundred forty-five thousand, two hundred fifty-two".