660553 has 4 divisors (see below), whose sum is σ = 670480. Its totient is φ = 650628.

The previous prime is 660547. The next prime is 660557. The reversal of 660553 is 355066.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 355066 = 2 ⋅177533.

It is a cyclic number.

It is not a de Polignac number, because 660553 - 2⁵ = 660521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (660557) 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, 4863 + ... + 4996.

It is an arithmetic number, because the mean of its divisors is an integer number (167620).

2⁶⁶⁰⁵⁵³ is an apocalyptic number.

It is an amenable number.

660553 is a deficient number, since it is larger than the sum of its proper divisors (9927).

660553 is an equidigital number, since it uses as much as digits as its factorization.

660553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9926.

The product of its (nonzero) digits is 2700, while the sum is 25.

The square root of 660553 is about 812.7441171734. The cubic root of 660553 is about 87.0901870072.

The spelling of 660553 in words is "six hundred sixty thousand, five hundred fifty-three".