660663 has 8 divisors (see below), whose sum is σ = 978800. Its totient is φ = 440424.

The previous prime is 660661. The next prime is 660683. The reversal of 660663 is 366066.

660663 is digitally balanced in base 2 and base 7, because in such bases it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 660663 - 2¹ = 660661 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 24469 = 660663 / (6 + 6 + 0 + 6 + 6 + 3).

It is a Duffinian number.

660663 is strictly pandigital in base 7.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660661) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12208 + ... + 12261.

It is an arithmetic number, because the mean of its divisors is an integer number (122350).

2⁶⁶⁰⁶⁶³ is an apocalyptic number.

660663 is a deficient number, since it is larger than the sum of its proper divisors (318137).

660663 is a wasteful number, since it uses less digits than its factorization.

660663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24478 (or 24472 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 27.

The square root of 660663 is about 812.8117863319. The cubic root of 660663 is about 87.0950210320.

It can be divided in two parts, 660 and 663, that multiplied together give a triangular number (437580 = T₉₃₅).

The spelling of 660663 in words is "six hundred sixty thousand, six hundred sixty-three".