665128225 has 6 divisors (see below), whose sum is σ = 824759030. Its totient is φ = 532102560.

The previous prime is 665128207. The next prime is 665128241. The reversal of 665128225 is 522821566.

It can be written as a sum of positive squares in 3 ways, for example, as 168194961 + 496933264 = 12969^2 + 22292^2 .

It is not a de Polignac number, because 665128225 - 2¹¹ = 665126177 is a prime.

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, 13302540 + ... + 13302589.

Almost surely, 2^665128225 is an apocalyptic number.

It is an amenable number.

665128225 is a deficient number, since it is larger than the sum of its proper divisors (159630805).

665128225 is a wasteful number, since it uses less digits than its factorization.

665128225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26605139 (or 26605134 counting only the distinct ones).

The product of its digits is 57600, while the sum is 37.

The square root of 665128225 is about 25790.0799727337. The cubic root of 665128225 is about 872.9079708814.

The spelling of 665128225 in words is "six hundred sixty-five million, one hundred twenty-eight thousand, two hundred twenty-five".