647868640853 has 6 divisors (see below), whose sum is σ = 753643112886. Its totient is φ = 555315977832.

The previous prime is 647868640831. The next prime is 647868640907. The reversal of 647868640853 is 358046868746.

It can be written as a sum of positive squares in only one way, i.e., 513742030564 + 134126610289 = 716758^2 + 366233^2 .

It is not a de Polignac number, because 647868640853 - 2⁸ = 647868640597 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 647868640853.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (647868643853) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6610904450 + ... + 6610904547.

It is an arithmetic number, because the mean of its divisors is an integer number (125607185481).

Almost surely, 2^647868640853 is an apocalyptic number.

It is an amenable number.

647868640853 is a deficient number, since it is larger than the sum of its proper divisors (105774472033).

647868640853 is a wasteful number, since it uses less digits than its factorization.

647868640853 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13221809011 (or 13221809004 counting only the distinct ones).

The product of its (nonzero) digits is 185794560, while the sum is 65.

The spelling of 647868640853 in words is "six hundred forty-seven billion, eight hundred sixty-eight million, six hundred forty thousand, eight hundred fifty-three".