665706215 has 8 divisors (see below), whose sum is σ = 802987728. Its totient is φ = 529804800.

The previous prime is 665706169. The next prime is 665706233. The reversal of 665706215 is 512607566.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 665706215 - 2¹⁸ = 665444071 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 343961 + ... + 345890.

It is an arithmetic number, because the mean of its divisors is an integer number (100373466).

Almost surely, 2^665706215 is an apocalyptic number.

665706215 is a deficient number, since it is larger than the sum of its proper divisors (137281513).

665706215 is a wasteful number, since it uses less digits than its factorization.

665706215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 690049.

The product of its (nonzero) digits is 75600, while the sum is 38.

The square root of 665706215 is about 25801.2832045230. The cubic root of 665706215 is about 873.1607472059.

The spelling of 665706215 in words is "six hundred sixty-five million, seven hundred six thousand, two hundred fifteen".