647686673 has 2 divisors, whose sum is σ = 647686674. Its totient is φ = 647686672.

The previous prime is 647686657. The next prime is 647686747. The reversal of 647686673 is 376686746.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 396527569 + 251159104 = 19913^2 + 15848^2 .

It is a cyclic number.

It is not a de Polignac number, because 647686673 - 2⁴ = 647686657 is a prime.

It is not a weakly prime, because it can be changed into another prime (647686873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323843336 + 323843337.

It is an arithmetic number, because the mean of its divisors is an integer number (323843337).

Almost surely, 2^647686673 is an apocalyptic number.

It is an amenable number.

647686673 is a deficient number, since it is larger than the sum of its proper divisors (1).

647686673 is an equidigital number, since it uses as much as digits as its factorization.

647686673 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6096384, while the sum is 53.

The square root of 647686673 is about 25449.6890550749. The cubic root of 647686673 is about 865.2102457074.

The spelling of 647686673 in words is "six hundred forty-seven million, six hundred eighty-six thousand, six hundred seventy-three".