199987656647 has 2 divisors, whose sum is σ = 199987656648. Its totient is φ = 199987656646.

The previous prime is 199987656619. The next prime is 199987656653. The reversal of 199987656647 is 746656789991.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-199987656647 is a prime.

It is a super-2 number, since 2×199987656647² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199987656667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99993828323 + 99993828324.

It is an arithmetic number, because the mean of its divisors is an integer number (99993828324).

Almost surely, 2^199987656647 is an apocalyptic number.

199987656647 is a deficient number, since it is larger than the sum of its proper divisors (1).

199987656647 is an equidigital number, since it uses as much as digits as its factorization.

199987656647 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1234517760, while the sum is 77.

The spelling of 199987656647 in words is "one hundred ninety-nine billion, nine hundred eighty-seven million, six hundred fifty-six thousand, six hundred forty-seven".