663660 has 48 divisors (see below), whose sum is σ = 2066400. Its totient is φ = 176832.

The previous prime is 663659. The next prime is 663661. The reversal of 663660 is 66366.

It is an interprime number because it is at equal distance from previous prime (663659) and next prime (663661).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (663661) 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 15 ways as a sum of consecutive naturals, for example, 75 + ... + 1154.

It is an arithmetic number, because the mean of its divisors is an integer number (43050).

2⁶⁶³⁶⁶⁰ is an apocalyptic number.

663660 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 663660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1033200).

663660 is an abundant number, since it is smaller than the sum of its proper divisors (1402740).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

663660 is a wasteful number, since it uses less digits than its factorization.

663660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1247 (or 1239 counting only the distinct ones).

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

The square root of 663660 is about 814.6533004905. The cubic root of 663660 is about 87.2265202841.

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

The spelling of 663660 in words is "six hundred sixty-three thousand, six hundred sixty".