188396640 has 144 divisors (see below), whose sum is σ = 658790496. Its totient is φ = 48998400.

The previous prime is 188396639. The next prime is 188396653. The reversal of 188396640 is 46693881.

It is a tau number, because it is divible by the number of its divisors (144).

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

It is a congruent number.

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, 57445 + ... + 60635.

It is an arithmetic number, because the mean of its divisors is an integer number (4574934).

Almost surely, 2^188396640 is an apocalyptic number.

188396640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 188396640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (329395248).

188396640 is an abundant number, since it is smaller than the sum of its proper divisors (470393856).

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

188396640 is a wasteful number, since it uses less digits than its factorization.

188396640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3253 (or 3242 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The square root of 188396640 is about 13725.7655524200. The cubic root of 188396640 is about 573.2680233280.

The spelling of 188396640 in words is "one hundred eighty-eight million, three hundred ninety-six thousand, six hundred forty".