647665705 has 8 divisors (see below), whose sum is σ = 778513032. Its totient is φ = 517256448.

The previous prime is 647665693. The next prime is 647665721. The reversal of 647665705 is 507566746.

It can be written as a sum of positive squares in 4 ways, for example, as 167003929 + 480661776 = 12923^2 + 21924^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 647665705 - 2¹³ = 647657513 is a prime.

It is a Duffinian number.

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 7 ways as a sum of consecutive naturals, for example, 106254 + ... + 112183.

It is an arithmetic number, because the mean of its divisors is an integer number (97314129).

Almost surely, 2^647665705 is an apocalyptic number.

It is an amenable number.

647665705 is a deficient number, since it is larger than the sum of its proper divisors (130847327).

647665705 is a wasteful number, since it uses less digits than its factorization.

647665705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 219035.

The product of its (nonzero) digits is 1058400, while the sum is 46.

The square root of 647665705 is about 25449.2771017174. The cubic root of 647665705 is about 865.2009089273.

The spelling of 647665705 in words is "six hundred forty-seven million, six hundred sixty-five thousand, seven hundred five".