647764321 has 6 divisors (see below), whose sum is σ = 683651922. Its totient is φ = 613671120.

The previous prime is 647764319. The next prime is 647764333. The reversal of 647764321 is 123467746.

It can be written as a sum of positive squares in only one way, i.e., 405619600 + 242144721 = 20140^2 + 15561^2 .

It is not a de Polignac number, because 647764321 - 2¹ = 647764319 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (647764361) 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 5 ways as a sum of consecutive naturals, for example, 896820 + ... + 897541.

It is an arithmetic number, because the mean of its divisors is an integer number (113941987).

Almost surely, 2^647764321 is an apocalyptic number.

It is an amenable number.

647764321 is a deficient number, since it is larger than the sum of its proper divisors (35887601).

647764321 is a wasteful number, since it uses less digits than its factorization.

647764321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1794399 (or 1794380 counting only the distinct ones).

The product of its digits is 169344, while the sum is 40.

The square root of 647764321 is about 25451.2145289768. The cubic root of 647764321 is about 865.2448196063.

The spelling of 647764321 in words is "six hundred forty-seven million, seven hundred sixty-four thousand, three hundred twenty-one".