665216726 has 8 divisors (see below), whose sum is σ = 999509544. Its totient is φ = 332046880.

The previous prime is 665216723. The next prime is 665216731. The reversal of 665216726 is 627612566.

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

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665216723) 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 3 ways as a sum of consecutive naturals, for example, 279260 + ... + 281631.

It is an arithmetic number, because the mean of its divisors is an integer number (124938693).

Almost surely, 2^665216726 is an apocalyptic number.

665216726 is a deficient number, since it is larger than the sum of its proper divisors (334292818).

665216726 is a wasteful number, since it uses less digits than its factorization.

665216726 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 561486.

The product of its digits is 181440, while the sum is 41.

The square root of 665216726 is about 25791.7957110396. The cubic root of 665216726 is about 872.9466851219.

The spelling of 665216726 in words is "six hundred sixty-five million, two hundred sixteen thousand, seven hundred twenty-six".