188109945 has 24 divisors (see below), whose sum is σ = 338135616. Its totient is φ = 100324656.

The previous prime is 188109941. The next prime is 188109973. The reversal of 188109945 is 549901881.

It is not a de Polignac number, because 188109945 - 2² = 188109941 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 188109945.

It is not an unprimeable number, because it can be changed into a prime (188109941) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 76197 + ... + 78626.

It is an arithmetic number, because the mean of its divisors is an integer number (14088984).

Almost surely, 2^188109945 is an apocalyptic number.

188109945 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

188109945 is a deficient number, since it is larger than the sum of its proper divisors (150025671).

188109945 is an equidigital number, since it uses as much as digits as its factorization.

188109945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154843 (or 154831 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 45.

The square root of 188109945 is about 13715.3178964251. The cubic root of 188109945 is about 572.9770830450.

The spelling of 188109945 in words is "one hundred eighty-eight million, one hundred nine thousand, nine hundred forty-five".