16663665 has 32 divisors (see below), whose sum is σ = 28569600. Its totient is φ = 8268480.

The previous prime is 16663657. The next prime is 16663681. The reversal of 16663665 is 56636661.

It is not a de Polignac number, because 16663665 - 2³ = 16663657 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16320 + ... + 17310.

It is an arithmetic number, because the mean of its divisors is an integer number (892800).

Almost surely, 2^16663665 is an apocalyptic number.

16663665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

16663665 is a deficient number, since it is larger than the sum of its proper divisors (11905935).

16663665 is a wasteful number, since it uses less digits than its factorization.

16663665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1077.

The product of its digits is 116640, while the sum is 39.

The square root of 16663665 is about 4082.1152604991. The cubic root of 16663665 is about 255.4211418406.

It can be divided in two parts, 1 and 6663665, that added together give a palindrome (6663666).

The spelling of 16663665 in words is "sixteen million, six hundred sixty-three thousand, six hundred sixty-five".