647320913 has 2 divisors, whose sum is σ = 647320914. Its totient is φ = 647320912.

The previous prime is 647320909. The next prime is 647320943. The reversal of 647320913 is 319023746.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 637411009 + 9909904 = 25247^2 + 3148^2 .

It is a cyclic number.

It is not a de Polignac number, because 647320913 - 2² = 647320909 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (647320943) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323660456 + 323660457.

It is an arithmetic number, because the mean of its divisors is an integer number (323660457).

Almost surely, 2^647320913 is an apocalyptic number.

It is an amenable number.

647320913 is a deficient number, since it is larger than the sum of its proper divisors (1).

647320913 is an equidigital number, since it uses as much as digits as its factorization.

647320913 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 27216, while the sum is 35.

The square root of 647320913 is about 25442.5020978677. The cubic root of 647320913 is about 865.0473485837.

The spelling of 647320913 in words is "six hundred forty-seven million, three hundred twenty thousand, nine hundred thirteen".