19666077779 has 2 divisors, whose sum is σ = 19666077780. Its totient is φ = 19666077778.

The previous prime is 19666077749. The next prime is 19666077793. The reversal of 19666077779 is 97777066691.

It is a strong prime.

It is an emirp because it is prime and its reverse (97777066691) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19666077779 - 2³² = 15371110483 is a prime.

It is not a weakly prime, because it can be changed into another prime (19666077749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9833038889 + 9833038890.

It is an arithmetic number, because the mean of its divisors is an integer number (9833038890).

Almost surely, 2^19666077779 is an apocalyptic number.

19666077779 is a deficient number, since it is larger than the sum of its proper divisors (1).

19666077779 is an equidigital number, since it uses as much as digits as its factorization.

19666077779 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 42007896, while the sum is 65.

The spelling of 19666077779 in words is "nineteen billion, six hundred sixty-six million, seventy-seven thousand, seven hundred seventy-nine".