647287779 has 4 divisors (see below), whose sum is σ = 863050376. Its totient is φ = 431525184.

The previous prime is 647287777. The next prime is 647287789. The reversal of 647287779 is 977782746.

It is a happy number.

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

It is not a de Polignac number, because 647287779 - 2¹ = 647287777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (647287777) 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, 107881294 + ... + 107881299.

It is an arithmetic number, because the mean of its divisors is an integer number (215762594).

Almost surely, 2^647287779 is an apocalyptic number.

647287779 is a deficient number, since it is larger than the sum of its proper divisors (215762597).

647287779 is a wasteful number, since it uses less digits than its factorization.

647287779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215762596.

The product of its digits is 8297856, while the sum is 57.

The square root of 647287779 is about 25441.8509350244. The cubic root of 647287779 is about 865.0325887908.

The spelling of 647287779 in words is "six hundred forty-seven million, two hundred eighty-seven thousand, seven hundred seventy-nine".