21125512 has 8 divisors (see below), whose sum is σ = 39610350. Its totient is φ = 10562752.

The previous prime is 21125501. The next prime is 21125521. The reversal of 21125512 is 21552112.

It can be written as a sum of positive squares in only one way, i.e., 10666756 + 10458756 = 3266^2 + 3234^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a self number, because there is not a number n which added to its sum of digits gives 21125512.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1320337 + ... + 1320352.

Almost surely, 2^21125512 is an apocalyptic number.

It is an amenable number.

21125512 is a deficient number, since it is larger than the sum of its proper divisors (18484838).

21125512 is a wasteful number, since it uses less digits than its factorization.

21125512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2640695 (or 2640691 counting only the distinct ones).

The product of its digits is 200, while the sum is 19.

The square root of 21125512 is about 4596.2497756323. The cubic root of 21125512 is about 276.4409739856.

Adding to 21125512 its reverse (21552112), we get a palindrome (42677624).

The spelling of 21125512 in words is "twenty-one million, one hundred twenty-five thousand, five hundred twelve".