6447665 has 12 divisors (see below), whose sum is σ = 9000756. Its totient is φ = 4421088.

The previous prime is 6447653. The next prime is 6447671. The reversal of 6447665 is 5667446.

It can be written as a sum of positive squares in 2 ways, for example, as 3236401 + 3211264 = 1799^2 + 1792^2 .

It is a de Polignac number, because none of the positive numbers 2^k-6447665 is a prime.

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12914 + ... + 13403.

It is an arithmetic number, because the mean of its divisors is an integer number (750063).

Almost surely, 2^6447665 is an apocalyptic number.

It is an amenable number.

6447665 is a deficient number, since it is larger than the sum of its proper divisors (2553091).

6447665 is a wasteful number, since it uses less digits than its factorization.

6447665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26336 (or 26329 counting only the distinct ones).

The product of its digits is 120960, while the sum is 38.

The square root of 6447665 is about 2539.2252755516. The cubic root of 6447665 is about 186.1233332402.

The spelling of 6447665 in words is "six million, four hundred forty-seven thousand, six hundred sixty-five".