115581978 has 48 divisors (see below), whose sum is σ = 273393120. Its totient is φ = 36496656.

The previous prime is 115581953. The next prime is 115582009. The reversal of 115581978 is 879185511.

115581978 is a `hidden beast` number, since 1 + 1 + 558 + 1 + 97 + 8 = 666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2976 + ... + 15492.

It is an arithmetic number, because the mean of its divisors is an integer number (5695690).

Almost surely, 2^115581978 is an apocalyptic number.

115581978 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 115581978, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (136696560).

115581978 is an abundant number, since it is smaller than the sum of its proper divisors (157811142).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

115581978 is a wasteful number, since it uses less digits than its factorization.

115581978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12553 (or 12541 counting only the distinct ones).

The product of its digits is 100800, while the sum is 45.

The square root of 115581978 is about 10750.9059153171. The cubic root of 115581978 is about 487.1133597056.

The spelling of 115581978 in words is "one hundred fifteen million, five hundred eighty-one thousand, nine hundred seventy-eight".