665789544 has 160 divisors (see below), whose sum is σ = 2189383680. Its totient is φ = 185037696.

The previous prime is 665789543. The next prime is 665789561. The reversal of 665789544 is 445987566.

665789544 is a `hidden beast` number, since 66 + 578 + 9 + 5 + 4 + 4 = 666.

665789544 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (665789543) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 165849 + ... + 169815.

It is an arithmetic number, because the mean of its divisors is an integer number (13683648).

Almost surely, 2^665789544 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665789544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1094691840).

665789544 is an abundant number, since it is smaller than the sum of its proper divisors (1523594136).

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

665789544 is a wasteful number, since it uses less digits than its factorization.

665789544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4029 (or 4016 counting only the distinct ones).

The product of its digits is 7257600, while the sum is 54.

The square root of 665789544 is about 25802.8979767777. The cubic root of 665789544 is about 873.1971779790.

The spelling of 665789544 in words is "six hundred sixty-five million, seven hundred eighty-nine thousand, five hundred forty-four".