665641000 has 64 divisors (see below), whose sum is σ = 1563082560. Its totient is φ = 265320000.

The previous prime is 665640971. The next prime is 665641019. The reversal of 665641000 is 146566.

It is a self number, because there is not a number n which added to its sum of digits gives 665641000.

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 15 ways as a sum of consecutive naturals, for example, 329995 + ... + 332005.

It is an arithmetic number, because the mean of its divisors is an integer number (24423165).

Almost surely, 2^665641000 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 665641000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (781541280).

665641000 is an abundant number, since it is smaller than the sum of its proper divisors (897441560).

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

665641000 is a wasteful number, since it uses less digits than its factorization.

665641000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2363 (or 2349 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 665641000 is about 25800.0193798377. The cubic root of 665641000 is about 873.1322336081.

Adding to 665641000 its reverse (146566), we get a palindrome (665787566).

The spelling of 665641000 in words is "six hundred sixty-five million, six hundred forty-one thousand".