19666772857 has 2 divisors, whose sum is σ = 19666772858. Its totient is φ = 19666772856.

The previous prime is 19666772843. The next prime is 19666772897. The reversal of 19666772857 is 75827766691.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19004276736 + 662496121 = 137856^2 + 25739^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19666772857 is a prime.

It is not a weakly prime, because it can be changed into another prime (19666772897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9833386428 + 9833386429.

It is an arithmetic number, because the mean of its divisors is an integer number (9833386429).

Almost surely, 2^19666772857 is an apocalyptic number.

It is an amenable number.

19666772857 is a deficient number, since it is larger than the sum of its proper divisors (1).

19666772857 is an equidigital number, since it uses as much as digits as its factorization.

19666772857 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 53343360, while the sum is 64.

The spelling of 19666772857 in words is "nineteen billion, six hundred sixty-six million, seven hundred seventy-two thousand, eight hundred fifty-seven".