665013888 has 640 divisors, whose sum is σ = 2665872000. Its totient is φ = 162570240.

The previous prime is 665013859. The next prime is 665013893. The reversal of 665013888 is 888310566.

665013888 is a `hidden beast` number, since 66 + 501 + 3 + 8 + 88 = 666.

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 79 ways as a sum of consecutive naturals, for example, 39118456 + ... + 39118472.

It is an arithmetic number, because the mean of its divisors is an integer number (4165425).

Almost surely, 2^665013888 is an apocalyptic number.

665013888 is a gapful number since it is divisible by the number (68) 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 665013888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1332936000).

665013888 is an abundant number, since it is smaller than the sum of its proper divisors (2000858112).

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

665013888 is a wasteful number, since it uses less digits than its factorization.

665013888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75 (or 40 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 45.

The square root of 665013888 is about 25787.8631918195. The cubic root of 665013888 is about 872.8579497504.

The spelling of 665013888 in words is "six hundred sixty-five million, thirteen thousand, eight hundred eighty-eight".