665023680 has 336 divisors, whose sum is σ = 2482047360. Its totient is φ = 163356672.

The previous prime is 665023673. The next prime is 665023691. The reversal of 665023680 is 86320566.

It is a super-3 number, since 3×665023680³ (a number of 27 digits) contains 333 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 14149417 + ... + 14149463.

Almost surely, 2^665023680 is an apocalyptic number.

665023680 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 665023680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1241023680).

665023680 is an abundant number, since it is smaller than the sum of its proper divisors (1817023680).

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

665023680 is a wasteful number, since it uses less digits than its factorization.

665023680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121 (or 74 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 665023680 is about 25788.0530478747. The cubic root of 665023680 is about 872.8622338630.

The spelling of 665023680 in words is "six hundred sixty-five million, twenty-three thousand, six hundred eighty".