188138915 has 8 divisors (see below), whose sum is σ = 239047200. Its totient is φ = 141657472.

The previous prime is 188138897. The next prime is 188138917. The reversal of 188138915 is 519831881.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 188138915 - 2⁶ = 188138851 is a prime.

It is not an unprimeable number, because it can be changed into a prime (188138917) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1106615 + ... + 1106784.

It is an arithmetic number, because the mean of its divisors is an integer number (29880900).

Almost surely, 2^188138915 is an apocalyptic number.

188138915 is a deficient number, since it is larger than the sum of its proper divisors (50908285).

188138915 is a wasteful number, since it uses less digits than its factorization.

188138915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2213421.

The product of its digits is 69120, while the sum is 44.

The square root of 188138915 is about 13716.3739741960. The cubic root of 188138915 is about 573.0064954436.

The spelling of 188138915 in words is "one hundred eighty-eight million, one hundred thirty-eight thousand, nine hundred fifteen".