1666566 has 48 divisors (see below), whose sum is σ = 4155840. Its totient is φ = 477360.

The previous prime is 1666559. The next prime is 1666589. The reversal of 1666566 is 6656661.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1666566.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3541 + ... + 3983.

It is an arithmetic number, because the mean of its divisors is an integer number (86580).

2^1666566 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1666566, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2077920).

1666566 is an abundant number, since it is smaller than the sum of its proper divisors (2489274).

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

1666566 is a wasteful number, since it uses less digits than its factorization.

1666566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 481 (or 478 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 1666566 is about 1290.9554601147. The cubic root of 1666566 is about 118.5607230310.

The spelling of 1666566 in words is "one million, six hundred sixty-six thousand, five hundred sixty-six".