665275815 has 32 divisors (see below), whose sum is σ = 1185028800. Its totient is φ = 354119040.

The previous prime is 665275811. The next prime is 665275829. The reversal of 665275815 is 518572566.

665275815 is a `hidden beast` number, since 6 + 65 + 2 + 7 + 581 + 5 = 666.

It is not a de Polignac number, because 665275815 - 2² = 665275811 is a prime.

It is a super-3 number, since 3×665275815³ (a number of 27 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665275811) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 68481 + ... + 77589.

It is an arithmetic number, because the mean of its divisors is an integer number (37032150).

Almost surely, 2^665275815 is an apocalyptic number.

665275815 is a deficient number, since it is larger than the sum of its proper divisors (519752985).

665275815 is a wasteful number, since it uses less digits than its factorization.

665275815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9664 (or 9658 counting only the distinct ones).

The product of its digits is 504000, while the sum is 45.

The square root of 665275815 is about 25792.9411855259. The cubic root of 665275815 is about 872.9725313448.

The spelling of 665275815 in words is "six hundred sixty-five million, two hundred seventy-five thousand, eight hundred fifteen".