647730913 has 4 divisors (see below), whose sum is σ = 650511108. Its totient is φ = 644950720.

The previous prime is 647730911. The next prime is 647730949. The reversal of 647730913 is 319037746.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 319037746 = 2 ⋅159518873.

It can be written as a sum of positive squares in 2 ways, for example, as 290634304 + 357096609 = 17048^2 + 18897^2 .

It is a cyclic number.

It is not a de Polignac number, because 647730913 - 2¹ = 647730911 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (647730911) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1389748 + ... + 1390213.

It is an arithmetic number, because the mean of its divisors is an integer number (162627777).

Almost surely, 2^647730913 is an apocalyptic number.

It is an amenable number.

647730913 is a deficient number, since it is larger than the sum of its proper divisors (2780195).

647730913 is a wasteful number, since it uses less digits than its factorization.

647730913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2780194.

The product of its (nonzero) digits is 95256, while the sum is 40.

The square root of 647730913 is about 25450.5582060591. The cubic root of 647730913 is about 865.2299445481.

The spelling of 647730913 in words is "six hundred forty-seven million, seven hundred thirty thousand, nine hundred thirteen".