665000020 has 12 divisors (see below), whose sum is σ = 1396500084. Its totient is φ = 266000000.

The previous prime is 664999949. The next prime is 665000027. The reversal of 665000020 is 20000566.

It can be written as a sum of positive squares in 2 ways, for example, as 420578064 + 244421956 = 20508^2 + 15634^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665000027) 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 3 ways as a sum of consecutive naturals, for example, 16624981 + ... + 16625020.

It is an arithmetic number, because the mean of its divisors is an integer number (116375007).

Almost surely, 2^665000020 is an apocalyptic number.

It is an amenable number.

665000020 is an abundant number, since it is smaller than the sum of its proper divisors (731500064).

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

665000020 is a wasteful number, since it uses less digits than its factorization.

665000020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33250010 (or 33250008 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 665000020 is about 25787.5943042386. The cubic root of 665000020 is about 872.8518822690.

Adding to 665000020 its reverse (20000566), we get a palindrome (685000586).

The spelling of 665000020 in words is "six hundred sixty-five million, twenty", and thus it is an aban number.