660257 has 4 divisors (see below), whose sum is σ = 711060. Its totient is φ = 609456.

The previous prime is 660251. The next prime is 660271. The reversal of 660257 is 752066.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 58081 + 602176 = 241^2 + 776^2 .

It is a cyclic number.

It is not a de Polignac number, because 660257 - 2⁴ = 660241 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (660251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25382 + ... + 25407.

It is an arithmetic number, because the mean of its divisors is an integer number (177765).

2⁶⁶⁰²⁵⁷ is an apocalyptic number.

It is an amenable number.

660257 is a deficient number, since it is larger than the sum of its proper divisors (50803).

660257 is a wasteful number, since it uses less digits than its factorization.

660257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50802.

The product of its (nonzero) digits is 2520, while the sum is 26.

The square root of 660257 is about 812.5619976346. The cubic root of 660257 is about 87.0771764201.

Subtracting 660257 from its reverse (752066), we obtain a square (91809 = 303²).

The spelling of 660257 in words is "six hundred sixty thousand, two hundred fifty-seven".