77790617979 has 4 divisors (see below), whose sum is σ = 103720823976. Its totient is φ = 51860411984.

The previous prime is 77790617959. The next prime is 77790617981. The reversal of 77790617979 is 97971609777.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 97971609777 = 3 ⋅32657203259.

It is a cyclic number.

It is not a de Polignac number, because 77790617979 - 2²¹ = 77788520827 is a prime.

It is not an unprimeable number, because it can be changed into a prime (77790617939) 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 in 3 ways as a sum of consecutive naturals, for example, 12965102994 + ... + 12965102999.

It is an arithmetic number, because the mean of its divisors is an integer number (25930205994).

Almost surely, 2^77790617979 is an apocalyptic number.

77790617979 is a deficient number, since it is larger than the sum of its proper divisors (25930205997).

77790617979 is a wasteful number, since it uses less digits than its factorization.

77790617979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25930205996.

The product of its (nonzero) digits is 73513818, while the sum is 69.

The spelling of 77790617979 in words is "seventy-seven billion, seven hundred ninety million, six hundred seventeen thousand, nine hundred seventy-nine".