666500 has 48 divisors (see below), whose sum is σ = 1537536. Its totient is φ = 252000.

The previous prime is 666493. The next prime is 666511. The reversal of 666500 is 5666.

666500 = T₇₉ + T₈₀ + ... + T₁₆₄.

It is a happy number.

It is a nialpdrome in base 10.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 666500.

It is an unprimeable number.

666500 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15479 + ... + 15521.

It is an arithmetic number, because the mean of its divisors is an integer number (32032).

2⁶⁶⁶⁵⁰⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (768768).

666500 is an abundant number, since it is smaller than the sum of its proper divisors (871036).

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

666500 is a wasteful number, since it uses less digits than its factorization.

666500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93 (or 81 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 23.

The square root of 666500 is about 816.3945124754. The cubic root of 666500 is about 87.3507660297.

The spelling of 666500 in words is "six hundred sixty-six thousand, five hundred".