16663517 has 4 divisors (see below), whose sum is σ = 17945340. Its totient is φ = 15381696.

The previous prime is 16663511. The next prime is 16663529. The reversal of 16663517 is 71536661.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7458361 + 9205156 = 2731^2 + 3034^2 .

It is a cyclic number.

It is not a de Polignac number, because 16663517 - 2⁴ = 16663501 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16663511) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 640892 + ... + 640917.

It is an arithmetic number, because the mean of its divisors is an integer number (4486335).

Almost surely, 2^16663517 is an apocalyptic number.

It is an amenable number.

16663517 is a deficient number, since it is larger than the sum of its proper divisors (1281823).

16663517 is a wasteful number, since it uses less digits than its factorization.

16663517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1281822.

The product of its digits is 22680, while the sum is 35.

The square root of 16663517 is about 4082.0971326023. The cubic root of 16663517 is about 255.4203856556.

The spelling of 16663517 in words is "sixteen million, six hundred sixty-three thousand, five hundred seventeen".