16649865 has 12 divisors (see below), whose sum is σ = 28859844. Its totient is φ = 8879904.

The previous prime is 16649839. The next prime is 16649879. The reversal of 16649865 is 56894661.

It can be written as a sum of positive squares in 2 ways, for example, as 10055241 + 6594624 = 3171^2 + 2568^2 .

It is not a de Polignac number, because 16649865 - 2¹⁴ = 16633481 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 369997 = 16649865 / (1 + 6 + 6 + 4 + 9 + 8 + 6 + 5).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 16649865.

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 11 ways as a sum of consecutive naturals, for example, 184954 + ... + 185043.

It is an arithmetic number, because the mean of its divisors is an integer number (2404987).

Almost surely, 2^16649865 is an apocalyptic number.

16649865 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

16649865 is a deficient number, since it is larger than the sum of its proper divisors (12209979).

16649865 is a wasteful number, since it uses less digits than its factorization.

16649865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 370008 (or 370005 counting only the distinct ones).

The product of its digits is 311040, while the sum is 45.

The square root of 16649865 is about 4080.4246102581. The cubic root of 16649865 is about 255.3506134339.

The spelling of 16649865 in words is "sixteen million, six hundred forty-nine thousand, eight hundred sixty-five".