639616056577 has 2 divisors, whose sum is σ = 639616056578. Its totient is φ = 639616056576.

The previous prime is 639616056571. The next prime is 639616056593. The reversal of 639616056577 is 775650616936.

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., 618725401281 + 20890655296 = 786591^2 + 144536^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-639616056577 is a prime.

It is a super-2 number, since 2×639616056577² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (639616056571) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319808028288 + 319808028289.

It is an arithmetic number, because the mean of its divisors is an integer number (319808028289).

Almost surely, 2^639616056577 is an apocalyptic number.

It is an amenable number.

639616056577 is a deficient number, since it is larger than the sum of its proper divisors (1).

639616056577 is an equidigital number, since it uses as much as digits as its factorization.

639616056577 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 42865200, while the sum is 61.

The spelling of 639616056577 in words is "six hundred thirty-nine billion, six hundred sixteen million, fifty-six thousand, five hundred seventy-seven".