665533815 has 12 divisors (see below), whose sum is σ = 1065013992. Its totient is φ = 354898080.

The previous prime is 665533787. The next prime is 665533849. The reversal of 665533815 is 518335566.

It is a happy number.

It is not a de Polignac number, because 665533815 - 2⁶ = 665533751 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 96585 + ... + 103245.

It is an arithmetic number, because the mean of its divisors is an integer number (88751166).

Almost surely, 2^665533815 is an apocalyptic number.

665533815 is a deficient number, since it is larger than the sum of its proper divisors (399480177).

665533815 is an frugal number, since it uses more digits than its factorization.

665533815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13330 (or 6669 counting only the distinct ones).

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

The square root of 665533815 is about 25797.9420690876. The cubic root of 665533815 is about 873.0853656507.

It can be divided in two parts, 6655 and 33815, that added together give a triangular number (40470 = T₂₈₄).

The spelling of 665533815 in words is "six hundred sixty-five million, five hundred thirty-three thousand, eight hundred fifteen".