77769372181 has 4 divisors (see below), whose sum is σ = 80451074700. Its totient is φ = 75087669664.

The previous prime is 77769372157. The next prime is 77769372209. The reversal of 77769372181 is 18127396777.

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 28011377956 + 49757994225 = 167366^2 + 223065^2 .

It is a cyclic number.

It is not a de Polignac number, because 77769372181 - 2²¹ = 77767275029 is a prime.

It is a super-2 number, since 2×77769372181² (a number of 23 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77769372481) 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, 1340851216 + ... + 1340851273.

It is an arithmetic number, because the mean of its divisors is an integer number (20112768675).

Almost surely, 2^77769372181 is an apocalyptic number.

It is an amenable number.

77769372181 is a deficient number, since it is larger than the sum of its proper divisors (2681702519).

77769372181 is a wasteful number, since it uses less digits than its factorization.

77769372181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2681702518.

The product of its digits is 6223392, while the sum is 58.

The spelling of 77769372181 in words is "seventy-seven billion, seven hundred sixty-nine million, three hundred seventy-two thousand, one hundred eighty-one".