77661046181 has 4 divisors (see below), whose sum is σ = 77662080012. Its totient is φ = 77660012352.

The previous prime is 77661046159. The next prime is 77661046193. The reversal of 77661046181 is 18164016677.

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 42192857281 + 35468188900 = 205409^2 + 188330^2 .

It is a cyclic number.

It is not a de Polignac number, because 77661046181 - 2³⁰ = 76587304357 is a prime.

It is a super-2 number, since 2×77661046181² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77661046081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 394586 + ... + 557691.

It is an arithmetic number, because the mean of its divisors is an integer number (19415520003).

Almost surely, 2^77661046181 is an apocalyptic number.

It is an amenable number.

77661046181 is a deficient number, since it is larger than the sum of its proper divisors (1033831).

77661046181 is an equidigital number, since it uses as much as digits as its factorization.

77661046181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1033830.

The product of its (nonzero) digits is 338688, while the sum is 47.

The spelling of 77661046181 in words is "seventy-seven billion, six hundred sixty-one million, forty-six thousand, one hundred eighty-one".