21252212 has 6 divisors (see below), whose sum is σ = 37191378. Its totient is φ = 10626104.

The previous prime is 21252211. The next prime is 21252223. The reversal of 21252212 is 21225212.

It can be written as a sum of positive squares in only one way, i.e., 19749136 + 1503076 = 4444^2 + 1226^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21252211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2656523 + ... + 2656530.

It is an arithmetic number, because the mean of its divisors is an integer number (6198563).

Almost surely, 2^21252212 is an apocalyptic number.

It is an amenable number.

21252212 is a deficient number, since it is larger than the sum of its proper divisors (15939166).

21252212 is a wasteful number, since it uses less digits than its factorization.

21252212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5313057 (or 5313055 counting only the distinct ones).

The product of its digits is 160, while the sum is 17.

The square root of 21252212 is about 4610.0121474894. The cubic root of 21252212 is about 276.9925232682.

Adding to 21252212 its reverse (21225212), we get a palindrome (42477424).

Subtracting from 21252212 its reverse (21225212), we obtain a cube (27000 = 30³).

The spelling of 21252212 in words is "twenty-one million, two hundred fifty-two thousand, two hundred twelve".