77785398617 has 4 divisors (see below), whose sum is σ = 80294605056. Its totient is φ = 75276192180.

The previous prime is 77785398601. The next prime is 77785398689. The reversal of 77785398617 is 71689358777.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 71689358777 = 521 ⋅137599537.

It is a cyclic number.

It is not a de Polignac number, because 77785398617 - 2⁴ = 77785398601 is a prime.

It is a super-3 number, since 3×77785398617³ (a number of 34 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77785398217) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1254603173 + ... + 1254603234.

It is an arithmetic number, because the mean of its divisors is an integer number (20073651264).

Almost surely, 2^77785398617 is an apocalyptic number.

It is an amenable number.

77785398617 is a deficient number, since it is larger than the sum of its proper divisors (2509206439).

77785398617 is a wasteful number, since it uses less digits than its factorization.

77785398617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2509206438.

The product of its digits is 124467840, while the sum is 68.

The spelling of 77785398617 in words is "seventy-seven billion, seven hundred eighty-five million, three hundred ninety-eight thousand, six hundred seventeen".