77947940771 has 2 divisors, whose sum is σ = 77947940772. Its totient is φ = 77947940770.

The previous prime is 77947940761. The next prime is 77947940887. The reversal of 77947940771 is 17704974977.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (17704974977) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77947940771 - 2¹⁰ = 77947939747 is a prime.

It is not a weakly prime, because it can be changed into another prime (77947940761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38973970385 + 38973970386.

It is an arithmetic number, because the mean of its divisors is an integer number (38973970386).

Almost surely, 2^77947940771 is an apocalyptic number.

77947940771 is a deficient number, since it is larger than the sum of its proper divisors (1).

77947940771 is an equidigital number, since it uses as much as digits as its factorization.

77947940771 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21781872, while the sum is 62.

The spelling of 77947940771 in words is "seventy-seven billion, nine hundred forty-seven million, nine hundred forty thousand, seven hundred seventy-one".