77716661777 has 4 divisors (see below), whose sum is σ = 79183013940. Its totient is φ = 76250309616.

The previous prime is 77716661753. The next prime is 77716661779.

It is a happy number.

77716661777 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 37443798016 + 40272863761 = 193504^2 + 200681^2 .

It is a cyclic number.

It is not a de Polignac number, because 77716661777 - 2⁶ = 77716661713 is a prime.

It is a super-2 number, since 2×77716661777² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77716661779) 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, 733176002 + ... + 733176107.

It is an arithmetic number, because the mean of its divisors is an integer number (19795753485).

Almost surely, 2^77716661777 is an apocalyptic number.

It is an amenable number.

77716661777 is a deficient number, since it is larger than the sum of its proper divisors (1466352163).

77716661777 is a wasteful number, since it uses less digits than its factorization.

77716661777 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1466352162.

The product of its digits is 25412184, while the sum is 62.

The spelling of 77716661777 in words is "seventy-seven billion, seven hundred sixteen million, six hundred sixty-one thousand, seven hundred seventy-seven".