21052225 has 6 divisors (see below), whose sum is σ = 26104790. Its totient is φ = 16841760.

The previous prime is 21052219. The next prime is 21052243. The reversal of 21052225 is 52225012.

It can be written as a sum of positive squares in 3 ways, for example, as 467856 + 20584369 = 684^2 + 4537^2 .

It is not a de Polignac number, because 21052225 - 2³ = 21052217 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 421020 + ... + 421069.

Almost surely, 2^21052225 is an apocalyptic number.

21052225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21052225 is a deficient number, since it is larger than the sum of its proper divisors (5052565).

21052225 is an equidigital number, since it uses as much as digits as its factorization.

21052225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 842099 (or 842094 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 19.

The square root of 21052225 is about 4588.2703712837. The cubic root of 21052225 is about 276.1209343653.

Adding to 21052225 its reverse (52225012), we get a palindrome (73277237).

The spelling of 21052225 in words is "twenty-one million, fifty-two thousand, two hundred twenty-five".