21252122 has 4 divisors (see below), whose sum is σ = 31878186. Its totient is φ = 10626060.

The previous prime is 21252113. The next prime is 21252137. The reversal of 21252122 is 22125212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 19175641 + 2076481 = 4379^2 + 1441^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21252122.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5313029 + ... + 5313032.

Almost surely, 2^21252122 is an apocalyptic number.

21252122 is a deficient number, since it is larger than the sum of its proper divisors (10626064).

21252122 is a wasteful number, since it uses less digits than its factorization.

21252122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10626063.

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

The square root of 21252122 is about 4610.0023861165. The cubic root of 21252122 is about 276.9921322601.

Adding to 21252122 its reverse (22125212), we get a palindrome (43377334).

The spelling of 21252122 in words is "twenty-one million, two hundred fifty-two thousand, one hundred twenty-two".