221500225 has 12 divisors (see below), whose sum is σ = 290817324. Its totient is φ = 166776320.

The previous prime is 221500207. The next prime is 221500261. The reversal of 221500225 is 522005122.

221500225 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 6 ways, for example, as 9535744 + 211964481 = 3088^2 + 14559^2 .

It is not a de Polignac number, because 221500225 - 2¹¹ = 221498177 is a prime.

It is a Duffinian number.

It is a congruent number.

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, 260164 + ... + 261013.

It is an arithmetic number, because the mean of its divisors is an integer number (24234777).

Almost surely, 2^221500225 is an apocalyptic number.

221500225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

221500225 is a deficient number, since it is larger than the sum of its proper divisors (69317099).

221500225 is a wasteful number, since it uses less digits than its factorization.

221500225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 521204 (or 521199 counting only the distinct ones).

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

The square root of 221500225 is about 14882.8836251581. The cubic root of 221500225 is about 605.0501745606.

Adding to 221500225 its reverse (522005122), we get a palindrome (743505347).

The spelling of 221500225 in words is "two hundred twenty-one million, five hundred thousand, two hundred twenty-five".