665317440 has 336 divisors, whose sum is σ = 2464929792. Its totient is φ = 164118528.

The previous prime is 665317439. The next prime is 665317441. The reversal of 665317440 is 44713566.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (665317439) and next prime (665317441).

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 665317395 and 665317404.

It is not an unprimeable number, because it can be changed into a prime (665317441) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5238657 + ... + 5238783.

Almost surely, 2^665317440 is an apocalyptic number.

665317440 is a gapful number since it is divisible by the number (60) 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 665317440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1232464896).

665317440 is an abundant number, since it is smaller than the sum of its proper divisors (1799612352).

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

665317440 is a wasteful number, since it uses less digits than its factorization.

665317440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274 (or 261 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 36.

The square root of 665317440 is about 25793.7480797189. The cubic root of 665317440 is about 872.9907376902.

The spelling of 665317440 in words is "six hundred sixty-five million, three hundred seventeen thousand, four hundred forty".