21043225 has 12 divisors (see below), whose sum is σ = 29821504. Its totient is φ = 14429520.

The previous prime is 21043223. The next prime is 21043237. The reversal of 21043225 is 52234012.

It is not a de Polignac number, because 21043225 - 2¹ = 21043223 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21043223) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 59949 + ... + 60298.

Almost surely, 2^21043225 is an apocalyptic number.

21043225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21043225 is a deficient number, since it is larger than the sum of its proper divisors (8778279).

21043225 is a wasteful number, since it uses less digits than its factorization.

21043225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120264 (or 120259 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 21043225 is about 4587.2895047075. The cubic root of 21043225 is about 276.0815807637.

Adding to 21043225 its reverse (52234012), we get a palindrome (73277237).

It can be divided in two parts, 2104 and 3225, that added together give a square (5329 = 73²).

The spelling of 21043225 in words is "twenty-one million, forty-three thousand, two hundred twenty-five".