665023681 has 32 divisors (see below), whose sum is σ = 805342208. Its totient is φ = 537243840.

The previous prime is 665023673. The next prime is 665023691. The reversal of 665023681 is 186320566.

665023681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 665023681 - 2³ = 665023673 is a prime.

It is a super-3 number, since 3×665023681³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 665023681.

It is not an unprimeable number, because it can be changed into a prime (665023631) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2349766 + ... + 2350048.

It is an arithmetic number, because the mean of its divisors is an integer number (25166944).

Almost surely, 2^665023681 is an apocalyptic number.

It is an amenable number.

665023681 is a deficient number, since it is larger than the sum of its proper divisors (140318527).

665023681 is a wasteful number, since it uses less digits than its factorization.

665023681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 581.

The product of its (nonzero) digits is 51840, while the sum is 37.

The square root of 665023681 is about 25788.0530672635. The cubic root of 665023681 is about 872.8622343005.

The spelling of 665023681 in words is "six hundred sixty-five million, twenty-three thousand, six hundred eighty-one".