1663866 has 24 divisors (see below), whose sum is σ = 3762720. Its totient is φ = 530376.

The previous prime is 1663861. The next prime is 1663867. The reversal of 1663866 is 6683661.

1663866 is a `hidden beast` number, since 16 + 638 + 6 + 6 = 666.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 1663866.

It is not an unprimeable number, because it can be changed into a prime (1663861) 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, 1596 + ... + 2423.

It is an arithmetic number, because the mean of its divisors is an integer number (156780).

2^1663866 is an apocalyptic number.

1663866 is an abundant number, since it is smaller than the sum of its proper divisors (2098854).

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

1663866 is a wasteful number, since it uses less digits than its factorization.

1663866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4050 (or 4047 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 1663866 is about 1289.9092991370. The cubic root of 1663866 is about 118.4966617657.

The spelling of 1663866 in words is "one million, six hundred sixty-three thousand, eight hundred sixty-six".