165547878778 has 16 divisors (see below), whose sum is σ = 255044342664. Its totient is φ = 80533293120.

The previous prime is 165547878773. The next prime is 165547878779. The reversal of 165547878778 is 877878745561.

165547878778 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 157773400849 + 7774477929 = 397207^2 + 88173^2 .

It is a super-2 number, since 2×165547878778² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 165547878778.

It is not an unprimeable number, because it can be changed into a prime (165547878773) 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 7 ways as a sum of consecutive naturals, for example, 2694376 + ... + 2755132.

Almost surely, 2^165547878778 is an apocalyptic number.

165547878778 is a deficient number, since it is larger than the sum of its proper divisors (89496463886).

165547878778 is a wasteful number, since it uses less digits than its factorization.

165547878778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97617.

The product of its digits is 737587200, while the sum is 73.

The spelling of 165547878778 in words is "one hundred sixty-five billion, five hundred forty-seven million, eight hundred seventy-eight thousand, seven hundred seventy-eight".