1666587 has 16 divisors (see below), whose sum is σ = 2417408. Its totient is φ = 1015200.

The previous prime is 1666559. The next prime is 1666589. The reversal of 1666587 is 7856661.

It is not a de Polignac number, because 1666587 - 2⁶ = 1666523 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666589) 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, 5748 + ... + 6030.

It is an arithmetic number, because the mean of its divisors is an integer number (151088).

2^1666587 is an apocalyptic number.

1666587 is a deficient number, since it is larger than the sum of its proper divisors (750821).

1666587 is a wasteful number, since it uses less digits than its factorization.

1666587 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 450.

The product of its digits is 60480, while the sum is 39.

The square root of 1666587 is about 1290.9635935998. The cubic root of 1666587 is about 118.5612210140.

The spelling of 1666587 in words is "one million, six hundred sixty-six thousand, five hundred eighty-seven".