77947940887 has 2 divisors, whose sum is σ = 77947940888. Its totient is φ = 77947940886.

The previous prime is 77947940771. The next prime is 77947940909. The reversal of 77947940887 is 78804974977.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 77947940887 - 2¹¹ = 77947938839 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77947950887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38973970443 + 38973970444.

It is an arithmetic number, because the mean of its divisors is an integer number (38973970444).

Almost surely, 2^77947940887 is an apocalyptic number.

77947940887 is a deficient number, since it is larger than the sum of its proper divisors (1).

77947940887 is an equidigital number, since it uses as much as digits as its factorization.

77947940887 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 199148544, while the sum is 70.

The spelling of 77947940887 in words is "seventy-seven billion, nine hundred forty-seven million, nine hundred forty thousand, eight hundred eighty-seven".