647711761 has 2 divisors, whose sum is σ = 647711762. Its totient is φ = 647711760.

The previous prime is 647711719. The next prime is 647711773. The reversal of 647711761 is 167117746.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 593409600 + 54302161 = 24360^2 + 7369^2 .

It is a cyclic number.

It is not a de Polignac number, because 647711761 - 2⁹ = 647711249 is a prime.

It is a super-2 number, since 2×647711761² = 839061050675442242, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (647751761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323855880 + 323855881.

It is an arithmetic number, because the mean of its divisors is an integer number (323855881).

Almost surely, 2^647711761 is an apocalyptic number.

It is an amenable number.

647711761 is a deficient number, since it is larger than the sum of its proper divisors (1).

647711761 is an equidigital number, since it uses as much as digits as its factorization.

647711761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 49392, while the sum is 40.

The square root of 647711761 is about 25450.1819443398. The cubic root of 647711761 is about 865.2214168057.

The spelling of 647711761 in words is "six hundred forty-seven million, seven hundred eleven thousand, seven hundred sixty-one".