665967744 has 288 divisors, whose sum is σ = 2178206940. Its totient is φ = 201553920.

The previous prime is 665967721. The next prime is 665967749. The reversal of 665967744 is 447769566.

665967744 is a `hidden beast` number, since 6 + 6 + 596 + 7 + 7 + 44 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 514382400 + 151585344 = 22680^2 + 12312^2 .

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (54).

Its product of digits (7620480) is a multiple of the sum of its prime factors (112).

It is not an unprimeable number, because it can be changed into a prime (665967749) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 10917474 + ... + 10917534.

Almost surely, 2^665967744 is an apocalyptic number.

665967744 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 665967744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1089103470).

665967744 is an abundant number, since it is smaller than the sum of its proper divisors (1512239196).

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

665967744 is an frugal number, since it uses more digits than its factorization.

665967744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112 (or 79 counting only the distinct ones).

The product of its digits is 7620480, while the sum is 54.

The square root of 665967744 is about 25806.3508462549. The cubic root of 665967744 is about 873.2750753957.

The spelling of 665967744 in words is "six hundred sixty-five million, nine hundred sixty-seven thousand, seven hundred forty-four".