188400728 has 32 divisors (see below), whose sum is σ = 370712160. Its totient is φ = 89591040.

The previous prime is 188400727. The next prime is 188400761. The reversal of 188400728 is 827004881.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 188400691 and 188400700.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (188400727) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 30476 + ... + 36132.

It is an arithmetic number, because the mean of its divisors is an integer number (11584755).

Almost surely, 2^188400728 is an apocalyptic number.

It is an amenable number.

188400728 is a deficient number, since it is larger than the sum of its proper divisors (182311432).

188400728 is a wasteful number, since it uses less digits than its factorization.

188400728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5867 (or 5863 counting only the distinct ones).

The product of its (nonzero) digits is 28672, while the sum is 38.

The square root of 188400728 is about 13725.9144686247. The cubic root of 188400728 is about 573.2721697267.

The spelling of 188400728 in words is "one hundred eighty-eight million, four hundred thousand, seven hundred twenty-eight".