77065951681 has 4 divisors (see below), whose sum is σ = 77067062212. Its totient is φ = 77064841152.

The previous prime is 77065951667. The next prime is 77065951687. The reversal of 77065951681 is 18615956077.

It is a happy number.

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 5327686081 + 71738265600 = 72991^2 + 267840^2 .

It is a cyclic number.

It is not a de Polignac number, because 77065951681 - 2⁵ = 77065951649 is a prime.

It is a super-2 number, since 2×77065951681² (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 (77065951687) 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, 443700 + ... + 592453.

It is an arithmetic number, because the mean of its divisors is an integer number (19266765553).

Almost surely, 2^77065951681 is an apocalyptic number.

It is an amenable number.

77065951681 is a deficient number, since it is larger than the sum of its proper divisors (1110531).

77065951681 is a wasteful number, since it uses less digits than its factorization.

77065951681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1110530.

The product of its (nonzero) digits is 3175200, while the sum is 55.

The spelling of 77065951681 in words is "seventy-seven billion, sixty-five million, nine hundred fifty-one thousand, six hundred eighty-one".