665511380 has 24 divisors (see below), whose sum is σ = 1402780680. Its totient is φ = 265212800.

The previous prime is 665511373. The next prime is 665511383. The reversal of 665511380 is 83115566.

It can be written as a sum of positive squares in 4 ways, for example, as 14853316 + 650658064 = 3854^2 + 25508^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 665511380.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665511383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 56471 + ... + 67230.

It is an arithmetic number, because the mean of its divisors is an integer number (58449195).

Almost surely, 2^665511380 is an apocalyptic number.

It is an amenable number.

665511380 is an abundant number, since it is smaller than the sum of its proper divisors (737269300).

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

665511380 is a wasteful number, since it uses less digits than its factorization.

665511380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123979 (or 123977 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 35.

The square root of 665511380 is about 25797.5072439180. The cubic root of 665511380 is about 873.0755550346.

The spelling of 665511380 in words is "six hundred sixty-five million, five hundred eleven thousand, three hundred eighty".