1666287 has 12 divisors (see below), whose sum is σ = 2750800. Its totient is φ = 952128.

The previous prime is 1666279. The next prime is 1666297. The reversal of 1666287 is 7826661.

It is a happy number.

It is not a de Polignac number, because 1666287 - 2³ = 1666279 is a prime.

It is a Duffinian number.

1666287 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666237) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13162 + ... + 13287.

2^1666287 is an apocalyptic number.

1666287 is a deficient number, since it is larger than the sum of its proper divisors (1084513).

1666287 is a wasteful number, since it uses less digits than its factorization.

1666287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26462 (or 26459 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 1666287 is about 1290.8473960930. The cubic root of 1666287 is about 118.5541065738.

It can be divided in two parts, 1666 and 287, that added together give a triangular number (1953 = T₆₂).

The spelling of 1666287 in words is "one million, six hundred sixty-six thousand, two hundred eighty-seven".