665751 has 8 divisors (see below), whose sum is σ = 891760. Its totient is φ = 441792.

The previous prime is 665747. The next prime is 665761. The reversal of 665751 is 157566.

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

It is not a de Polignac number, because 665751 - 2² = 665747 is a prime.

It is a Duffinian number.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665761) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 585 + ... + 1293.

It is an arithmetic number, because the mean of its divisors is an integer number (111470).

2⁶⁶⁵⁷⁵¹ is an apocalyptic number.

665751 is a deficient number, since it is larger than the sum of its proper divisors (226009).

665751 is a wasteful number, since it uses less digits than its factorization.

665751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1025.

The product of its digits is 6300, while the sum is 30.

The square root of 665751 is about 815.9356592281. The cubic root of 665751 is about 87.3180327228.

The spelling of 665751 in words is "six hundred sixty-five thousand, seven hundred fifty-one".