647664071 has 2 divisors, whose sum is σ = 647664072. Its totient is φ = 647664070.

The previous prime is 647664067. The next prime is 647664257. The reversal of 647664071 is 170466746.

It is a happy number.

647664071 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 647664071 - 2² = 647664067 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (647664271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323832035 + 323832036.

It is an arithmetic number, because the mean of its divisors is an integer number (323832036).

Almost surely, 2^647664071 is an apocalyptic number.

647664071 is a deficient number, since it is larger than the sum of its proper divisors (1).

647664071 is an equidigital number, since it uses as much as digits as its factorization.

647664071 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 169344, while the sum is 41.

The square root of 647664071 is about 25449.2449986242. The cubic root of 647664071 is about 865.2001813196.

The spelling of 647664071 in words is "six hundred forty-seven million, six hundred sixty-four thousand, seventy-one".