647917 has 2 divisors, whose sum is σ = 647918. Its totient is φ = 647916.

The previous prime is 647909. The next prime is 647951. The reversal of 647917 is 719746.

It is an a-pointer prime, because the next prime (647951) can be obtained adding 647917 to its sum of digits (34).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 599076 + 48841 = 774^2 + 221^2 .

It is a cyclic number.

It is not a de Polignac number, because 647917 - 2³ = 647909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (647987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323958 + 323959.

It is an arithmetic number, because the mean of its divisors is an integer number (323959).

2⁶⁴⁷⁹¹⁷ is an apocalyptic number.

It is an amenable number.

647917 is a deficient number, since it is larger than the sum of its proper divisors (1).

647917 is an equidigital number, since it uses as much as digits as its factorization.

647917 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10584, while the sum is 34.

The square root of 647917 is about 804.9329164595. The cubic root of 647917 is about 86.5312794090.

The spelling of 647917 in words is "six hundred forty-seven thousand, nine hundred seventeen".