77777121979 has 2 divisors, whose sum is σ = 77777121980. Its totient is φ = 77777121978.

The previous prime is 77777121973. The next prime is 77777122091. The reversal of 77777121979 is 97912177777.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77777121979 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 77777121979.

It is not a weakly prime, because it can be changed into another prime (77777121973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38888560989 + 38888560990.

It is an arithmetic number, because the mean of its divisors is an integer number (38888560990).

Almost surely, 2^77777121979 is an apocalyptic number.

77777121979 is a deficient number, since it is larger than the sum of its proper divisors (1).

77777121979 is an equidigital number, since it uses as much as digits as its factorization.

77777121979 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 19059138, while the sum is 64.

The spelling of 77777121979 in words is "seventy-seven billion, seven hundred seventy-seven million, one hundred twenty-one thousand, nine hundred seventy-nine".