1663986 has 8 divisors (see below), whose sum is σ = 3327984. Its totient is φ = 554660.

The previous prime is 1663973. The next prime is 1663997. The reversal of 1663986 is 6893661.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

1663986 is an admirable number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 138660 + ... + 138671.

It is an arithmetic number, because the mean of its divisors is an integer number (415998).

2^1663986 is an apocalyptic number.

1663986 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

1663986 is a wasteful number, since it uses less digits than its factorization.

1663986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 277336.

The product of its digits is 46656, while the sum is 39.

The square root of 1663986 is about 1289.9558131967. The cubic root of 1663986 is about 118.4995104041.

The spelling of 1663986 in words is "one million, six hundred sixty-three thousand, nine hundred eighty-six".