1663686 has 16 divisors (see below), whose sum is σ = 3697200. Its totient is φ = 554544.

The previous prime is 1663681. The next prime is 1663687. The reversal of 1663686 is 6863661.

1663686 is a `hidden beast` number, since 16 + 636 + 8 + 6 = 666.

It is a super-2 number, since 2×1663686² = 5535702213192, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1663686.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1663681) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15351 + ... + 15458.

It is an arithmetic number, because the mean of its divisors is an integer number (231075).

2^1663686 is an apocalyptic number.

1663686 is an abundant number, since it is smaller than the sum of its proper divisors (2033514).

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

1663686 is a wasteful number, since it uses less digits than its factorization.

1663686 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30820 (or 30814 counting only the distinct ones).

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

The square root of 1663686 is about 1289.8395249022. The cubic root of 1663686 is about 118.4923885513.

The spelling of 1663686 in words is "one million, six hundred sixty-three thousand, six hundred eighty-six".