666487 has 4 divisors (see below), whose sum is σ = 673456. Its totient is φ = 659520.

The previous prime is 666467. The next prime is 666493. The reversal of 666487 is 784666.

666487 is nontrivially palindromic in base 9.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 784666 = 2 ⋅392333.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666487 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666427) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3339 + ... + 3532.

It is an arithmetic number, because the mean of its divisors is an integer number (168364).

2⁶⁶⁶⁴⁸⁷ is an apocalyptic number.

666487 is a deficient number, since it is larger than the sum of its proper divisors (6969).

666487 is an equidigital number, since it uses as much as digits as its factorization.

666487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6968.

The product of its digits is 48384, while the sum is 37.

The square root of 666487 is about 816.3865505997. The cubic root of 666487 is about 87.3501981040.

The spelling of 666487 in words is "six hundred sixty-six thousand, four hundred eighty-seven".