665730 has 48 divisors (see below), whose sum is σ = 1867320. Its totient is φ = 163584.

The previous prime is 665723. The next prime is 665747. The reversal of 665730 is 37566.

665730 is a `hidden beast` number, since 6 + 657 + 3 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 294849 + 370881 = 543^2 + 609^2 .

It is a junction number, because it is equal to n+sod(n) for n = 665694 and 665703.

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, 886 + ... + 1454.

2⁶⁶⁵⁷³⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665730, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (933660).

665730 is an abundant number, since it is smaller than the sum of its proper divisors (1201590).

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

665730 is a wasteful number, since it uses less digits than its factorization.

665730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 595 (or 592 counting only the distinct ones).

The product of its (nonzero) digits is 3780, while the sum is 27.

The square root of 665730 is about 815.9227904649. The cubic root of 665730 is about 87.3171146128.

The spelling of 665730 in words is "six hundred sixty-five thousand, seven hundred thirty".