647711657 has 2 divisors, whose sum is σ = 647711658. Its totient is φ = 647711656.

The previous prime is 647711639. The next prime is 647711693. The reversal of 647711657 is 756117746.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 533563801 + 114147856 = 23099^2 + 10684^2 .

It is a cyclic number.

It is not a de Polignac number, because 647711657 - 2⁸ = 647711401 is a prime.

It is a super-2 number, since 2×647711657² = 839060781227371298, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (647711627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323855828 + 323855829.

It is an arithmetic number, because the mean of its divisors is an integer number (323855829).

Almost surely, 2^647711657 is an apocalyptic number.

It is an amenable number.

647711657 is a deficient number, since it is larger than the sum of its proper divisors (1).

647711657 is an equidigital number, since it uses as much as digits as its factorization.

647711657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 246960, while the sum is 44.

The square root of 647711657 is about 25450.1799011323. The cubic root of 647711657 is about 865.2213704975.

The spelling of 647711657 in words is "six hundred forty-seven million, seven hundred eleven thousand, six hundred fifty-seven".