21053225 has 12 divisors (see below), whose sum is σ = 27642204. Its totient is φ = 15851520.

The previous prime is 21053203. The next prime is 21053267. The reversal of 21053225 is 52235012.

It can be written as a sum of positive squares in 6 ways, for example, as 3481 + 21049744 = 59^2 + 4588^2 .

It is not a de Polignac number, because 21053225 - 2¹⁸ = 20791081 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21053197 and 21053206.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 24344 + ... + 25193.

It is an arithmetic number, because the mean of its divisors is an integer number (2303517).

Almost surely, 2^21053225 is an apocalyptic number.

21053225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21053225 is a deficient number, since it is larger than the sum of its proper divisors (6588979).

21053225 is a wasteful number, since it uses less digits than its factorization.

21053225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49564 (or 49559 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 20.

The square root of 21053225 is about 4588.3793435155. The cubic root of 21053225 is about 276.1253062953.

Adding to 21053225 its reverse (52235012), we get a palindrome (73288237).

It can be divided in two parts, 210 and 53225, that added together give a palindrome (53435).

The spelling of 21053225 in words is "twenty-one million, fifty-three thousand, two hundred twenty-five".