665695968 has 144 divisors (see below), whose sum is σ = 2076689664. Its totient is φ = 186090240.

The previous prime is 665695937. The next prime is 665695981. The reversal of 665695968 is 869596566.

It is a super-2 number, since 2×665695968² = 886302243622914048, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 219583 + ... + 222593.

It is an arithmetic number, because the mean of its divisors is an integer number (14421456).

Almost surely, 2^665695968 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 665695968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1038344832).

665695968 is an abundant number, since it is smaller than the sum of its proper divisors (1410993696).

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

665695968 is a wasteful number, since it uses less digits than its factorization.

665695968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3085 (or 3070 counting only the distinct ones).

The product of its digits is 20995200, while the sum is 60.

The square root of 665695968 is about 25801.0846283640. The cubic root of 665695968 is about 873.1562670894.

The spelling of 665695968 in words is "six hundred sixty-five million, six hundred ninety-five thousand, nine hundred sixty-eight".