66520225 has 6 divisors (see below), whose sum is σ = 82485110. Its totient is φ = 53216160.

The previous prime is 66520219. The next prime is 66520243. The reversal of 66520225 is 52202566.

66520225 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 3 ways, for example, as 130321 + 66389904 = 361^2 + 8148^2 .

It is not a de Polignac number, because 66520225 - 2³ = 66520217 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 66520193 and 66520202.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1330380 + ... + 1330429.

Almost surely, 2^66520225 is an apocalyptic number.

It is an amenable number.

66520225 is a deficient number, since it is larger than the sum of its proper divisors (15964885).

66520225 is a wasteful number, since it uses less digits than its factorization.

66520225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2660819 (or 2660814 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 28.

The square root of 66520225 is about 8155.9931951909. The cubic root of 66520225 is about 405.1830194505.

The spelling of 66520225 in words is "sixty-six million, five hundred twenty thousand, two hundred twenty-five".