665444388 has 96 divisors (see below), whose sum is σ = 1839136768. Its totient is φ = 183254400.

The previous prime is 665444387. The next prime is 665444407. The reversal of 665444388 is 883444566.

It is not an unprimeable number, because it can be changed into a prime (665444383) 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 31 ways as a sum of consecutive naturals, for example, 1095981 + ... + 1096587.

Almost surely, 2^665444388 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 665444388, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (919568384).

665444388 is an abundant number, since it is smaller than the sum of its proper divisors (1173692380).

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

665444388 is a wasteful number, since it uses less digits than its factorization.

665444388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1073 (or 1071 counting only the distinct ones).

The product of its digits is 2211840, while the sum is 48.

The square root of 665444388 is about 25796.2087912158. The cubic root of 665444388 is about 873.0462587460.

The spelling of 665444388 in words is "six hundred sixty-five million, four hundred forty-four thousand, three hundred eighty-eight".