660557 has 2 divisors, whose sum is σ = 660558. Its totient is φ = 660556.

The previous prime is 660547. The next prime is 660559. The reversal of 660557 is 755066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 538756 + 121801 = 734^2 + 349^2 .

It is a cyclic number.

It is not a de Polignac number, because 660557 - 2⁶ = 660493 is a prime.

Together with 660559, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 660557.

It is not a weakly prime, because it can be changed into another prime (660559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330278 + 330279.

It is an arithmetic number, because the mean of its divisors is an integer number (330279).

2⁶⁶⁰⁵⁵⁷ is an apocalyptic number.

It is an amenable number.

660557 is a deficient number, since it is larger than the sum of its proper divisors (1).

660557 is an equidigital number, since it uses as much as digits as its factorization.

660557 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6300, while the sum is 29.

The square root of 660557 is about 812.7465779688. The cubic root of 660557 is about 87.0903627993.

The spelling of 660557 in words is "six hundred sixty thousand, five hundred fifty-seven".