647046809 has 4 divisors (see below), whose sum is σ = 685108404. Its totient is φ = 608985216.

The previous prime is 647046761. The next prime is 647046823. The reversal of 647046809 is 908640746.

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 510624409 + 136422400 = 22597^2 + 11680^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-647046809 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 647046809.

It is not an unprimeable number, because it can be changed into a prime (647046889) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 19030772 + ... + 19030805.

It is an arithmetic number, because the mean of its divisors is an integer number (171277101).

Almost surely, 2^647046809 is an apocalyptic number.

It is an amenable number.

647046809 is a deficient number, since it is larger than the sum of its proper divisors (38061595).

647046809 is a wasteful number, since it uses less digits than its factorization.

647046809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38061594.

The product of its (nonzero) digits is 290304, while the sum is 44.

The square root of 647046809 is about 25437.1147931522. The cubic root of 647046809 is about 864.9252317122.

The spelling of 647046809 in words is "six hundred forty-seven million, forty-six thousand, eight hundred nine".