77768065661 has 24 divisors (see below), whose sum is σ = 92131388064. Its totient is φ = 65071306560.

The previous prime is 77768065657. The next prime is 77768065667. The reversal of 77768065661 is 16656086777.

It is not a de Polignac number, because 77768065661 - 2² = 77768065657 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 77768065661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77768065667) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 584795 + ... + 705351.

It is an arithmetic number, because the mean of its divisors is an integer number (3838807836).

Almost surely, 2^77768065661 is an apocalyptic number.

It is an amenable number.

77768065661 is a deficient number, since it is larger than the sum of its proper divisors (14363322403).

77768065661 is a wasteful number, since it uses less digits than its factorization.

77768065661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120941 (or 120928 counting only the distinct ones).

The product of its (nonzero) digits is 17781120, while the sum is 59.

The spelling of 77768065661 in words is "seventy-seven billion, seven hundred sixty-eight million, sixty-five thousand, six hundred sixty-one".