647665537 has 2 divisors, whose sum is σ = 647665538. Its totient is φ = 647665536.

The previous prime is 647665519. The next prime is 647665607. The reversal of 647665537 is 735566746.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 545736321 + 101929216 = 23361^2 + 10096^2 .

It is a cyclic number.

It is not a de Polignac number, because 647665537 - 2¹⁹ = 647141249 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (647662537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323832768 + 323832769.

It is an arithmetic number, because the mean of its divisors is an integer number (323832769).

Almost surely, 2^647665537 is an apocalyptic number.

It is an amenable number.

647665537 is a deficient number, since it is larger than the sum of its proper divisors (1).

647665537 is an equidigital number, since it uses as much as digits as its factorization.

647665537 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3175200, while the sum is 49.

The square root of 647665537 is about 25449.2738010341. The cubic root of 647665537 is about 865.2008341182.

The spelling of 647665537 in words is "six hundred forty-seven million, six hundred sixty-five thousand, five hundred thirty-seven".