1563666 has 16 divisors (see below), whose sum is σ = 3368064. Its totient is φ = 481104.

The previous prime is 1563649. The next prime is 1563689. The reversal of 1563666 is 6663651.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9946 + ... + 10101.

It is an arithmetic number, because the mean of its divisors is an integer number (210504).

2^1563666 is an apocalyptic number.

1563666 is an abundant number, since it is smaller than the sum of its proper divisors (1804398).

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

1563666 is a wasteful number, since it uses less digits than its factorization.

1563666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20065.

The product of its digits is 19440, while the sum is 33.

The square root of 1563666 is about 1250.4663130209. The cubic root of 1563666 is about 116.0685781571.

The spelling of 1563666 in words is "one million, five hundred sixty-three thousand, six hundred sixty-six".