19768377557 has 2 divisors, whose sum is σ = 19768377558. Its totient is φ = 19768377556.

The previous prime is 19768377491. The next prime is 19768377641. The reversal of 19768377557 is 75577386791.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10174958641 + 9593418916 = 100871^2 + 97946^2 .

It is a cyclic number.

It is not a de Polignac number, because 19768377557 - 2⁸ = 19768377301 is a prime.

It is a super-2 number, since 2×19768377557² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 19768377493 and 19768377502.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19768377857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9884188778 + 9884188779.

It is an arithmetic number, because the mean of its divisors is an integer number (9884188779).

Almost surely, 2^19768377557 is an apocalyptic number.

It is an amenable number.

19768377557 is a deficient number, since it is larger than the sum of its proper divisors (1).

19768377557 is an equidigital number, since it uses as much as digits as its factorization.

19768377557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 77792400, while the sum is 65.

The spelling of 19768377557 in words is "nineteen billion, seven hundred sixty-eight million, three hundred seventy-seven thousand, five hundred fifty-seven".