665215566 has 32 divisors (see below), whose sum is σ = 1357840800. Its totient is φ = 217211904.

The previous prime is 665215541. The next prime is 665215567. The reversal of 665215566 is 665512566.

665215566 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665215567) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60166 + ... + 70358.

It is an arithmetic number, because the mean of its divisors is an integer number (42432525).

Almost surely, 2^665215566 is an apocalyptic number.

665215566 is an abundant number, since it is smaller than the sum of its proper divisors (692625234).

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

665215566 is a wasteful number, since it uses less digits than its factorization.

665215566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10420.

The product of its digits is 324000, while the sum is 42.

The square root of 665215566 is about 25791.7732232586. The cubic root of 665215566 is about 872.9461777089.

The spelling of 665215566 in words is "six hundred sixty-five million, two hundred fifteen thousand, five hundred sixty-six".