666501 has 16 divisors (see below), whose sum is σ = 1021440. Its totient is φ = 382320.

The previous prime is 666493. The next prime is 666511. The reversal of 666501 is 105666.

It is not a de Polignac number, because 666501 - 2³ = 666493 is a prime.

666501 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666511) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 96 + ... + 1158.

It is an arithmetic number, because the mean of its divisors is an integer number (63840).

2⁶⁶⁶⁵⁰¹ is an apocalyptic number.

It is an amenable number.

666501 is a deficient number, since it is larger than the sum of its proper divisors (354939).

666501 is a wasteful number, since it uses less digits than its factorization.

666501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1096.

The product of its (nonzero) digits is 1080, while the sum is 24.

The square root of 666501 is about 816.3951249242. The cubic root of 666501 is about 87.3508097160.

The spelling of 666501 in words is "six hundred sixty-six thousand, five hundred one".