666750 has 64 divisors (see below), whose sum is σ = 1916928. Its totient is φ = 151200.

The previous prime is 666749. The next prime is 666751. The reversal of 666750 is 57666.

It is an interprime number because it is at equal distance from previous prime (666749) and next prime (666751).

It is a Harshad number since it is a multiple of its sum of digits (30).

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 666750.

It is not an unprimeable number, because it can be changed into a prime (666751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5187 + ... + 5313.

It is an arithmetic number, because the mean of its divisors is an integer number (29952).

2⁶⁶⁶⁷⁵⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666750, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (958464).

666750 is an abundant number, since it is smaller than the sum of its proper divisors (1250178).

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

666750 is a wasteful number, since it uses less digits than its factorization.

666750 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154 (or 144 counting only the distinct ones).

The product of its (nonzero) digits is 7560, while the sum is 30.

The square root of 666750 is about 816.5476103694. The cubic root of 666750 is about 87.3616862406.

It can be divided in two parts, 666 and 750, that multiplied together give a triangular number (499500 = T₉₉₉).

The spelling of 666750 in words is "six hundred sixty-six thousand, seven hundred fifty".