115640388 has 18 divisors (see below), whose sum is σ = 292313294. Its totient is φ = 38546784.

The previous prime is 115640387. The next prime is 115640407. The reversal of 115640388 is 883046511.

115640388 is a `hidden beast` number, since 1 + 1 + 5 + 640 + 3 + 8 + 8 = 666.

It can be written as a sum of positive squares in only one way, i.e., 67864644 + 47775744 = 8238^2 + 6912^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 3212233 = 115640388 / (1 + 1 + 5 + 6 + 4 + 0 + 3 + 8 + 8).

It is not an unprimeable number, because it can be changed into a prime (115640387) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1606081 + ... + 1606152.

Almost surely, 2^115640388 is an apocalyptic number.

115640388 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

115640388 is an abundant number, since it is smaller than the sum of its proper divisors (176672906).

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

115640388 is a wasteful number, since it uses less digits than its factorization.

115640388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3212243 (or 3212238 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 115640388 is about 10753.6220874643. The cubic root of 115640388 is about 487.1954010421.

Adding to 115640388 its reverse (883046511), we get a palindrome (998686899).

The spelling of 115640388 in words is "one hundred fifteen million, six hundred forty thousand, three hundred eighty-eight".