665705120 has 48 divisors (see below), whose sum is σ = 1582805448. Its totient is φ = 264576000.

The previous prime is 665705119. The next prime is 665705143. The reversal of 665705120 is 21507566.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 422220304 + 243484816 = 20548^2 + 15604^2 .

It is a Harshad number since it is a multiple of its sum of digits (32).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11870 + ... + 38370.

Almost surely, 2^665705120 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665705120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (791402724).

665705120 is an abundant number, since it is smaller than the sum of its proper divisors (917100328).

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

665705120 is a wasteful number, since it uses less digits than its factorization.

665705120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26673 (or 26665 counting only the distinct ones).

The product of its (nonzero) digits is 12600, while the sum is 32.

The square root of 665705120 is about 25801.2619846394. The cubic root of 665705120 is about 873.1602684604.

The spelling of 665705120 in words is "six hundred sixty-five million, seven hundred five thousand, one hundred twenty".