665817984 has 192 divisors, whose sum is σ = 2154166560. Its totient is φ = 195858432.

The previous prime is 665817967. The next prime is 665818001. The reversal of 665817984 is 489718566.

665817984 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (665817967) and next prime (665818001).

It is a tau number, because it is divible by the number of its divisors (192).

It is a self number, because there is not a number n which added to its sum of digits gives 665817984.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 343482 + ... + 345414.

Almost surely, 2^665817984 is an apocalyptic number.

665817984 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665817984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1077083280).

665817984 is an abundant number, since it is smaller than the sum of its proper divisors (1488348576).

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

665817984 is a wasteful number, since it uses less digits than its factorization.

665817984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1989 (or 1974 counting only the distinct ones).

The product of its digits is 2903040, while the sum is 54.

The square root of 665817984 is about 25803.4490717811. The cubic root of 665817984 is about 873.2096110240.

It can be divided in two parts, 6658 and 17984, that added together give a palindrome (24642).

The spelling of 665817984 in words is "six hundred sixty-five million, eight hundred seventeen thousand, nine hundred eighty-four".