660521 has 2 divisors, whose sum is σ = 660522. Its totient is φ = 660520.

The previous prime is 660509. The next prime is 660529. The reversal of 660521 is 125066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 346921 + 313600 = 589^2 + 560^2 .

It is a cyclic number.

It is not a de Polignac number, because 660521 - 2¹⁰ = 659497 is a prime.

It is a Chen prime.

It is equal to p₅₃₆₀₆ and since 660521 and 53606 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 660493 and 660502.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 660521.

It is not a weakly prime, because it can be changed into another prime (660529) 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 as a sum of consecutive naturals, namely, 330260 + 330261.

It is an arithmetic number, because the mean of its divisors is an integer number (330261).

2⁶⁶⁰⁵²¹ is an apocalyptic number.

It is an amenable number.

660521 is a deficient number, since it is larger than the sum of its proper divisors (1).

660521 is an equidigital number, since it uses as much as digits as its factorization.

660521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 660521 is about 812.7244305421. The cubic root of 660521 is about 87.0887806446.

Adding to 660521 its reverse (125066), we get a palindrome (785587).

The spelling of 660521 in words is "six hundred sixty thousand, five hundred twenty-one".