665680288 has 216 divisors, whose sum is σ = 1759489452. Its totient is φ = 245661696.

The previous prime is 665680259. The next prime is 665680369. The reversal of 665680288 is 882086566.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 187470864 + 478209424 = 13692^2 + 21868^2 .

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 5890920 + ... + 5891032.

Almost surely, 2^665680288 is an apocalyptic number.

665680288 is a gapful number since it is divisible by the number (68) 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 665680288, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (879744726).

665680288 is an abundant number, since it is smaller than the sum of its proper divisors (1093809164).

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

665680288 is a wasteful number, since it uses less digits than its factorization.

665680288 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 184 (or 152 counting only the distinct ones).

The product of its (nonzero) digits is 1105920, while the sum is 49.

The square root of 665680288 is about 25800.7807633800. The cubic root of 665680288 is about 873.1494115085.

The spelling of 665680288 in words is "six hundred sixty-five million, six hundred eighty thousand, two hundred eighty-eight".