665121361 has 8 divisors (see below), whose sum is σ = 686169344. Its totient is φ = 644235120.

The previous prime is 665121343. The next prime is 665121371. The reversal of 665121361 is 163121566.

665121361 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a de Polignac number, because none of the positive numbers 2^k-665121361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665121371) 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, 32055 + ... + 48556.

It is an arithmetic number, because the mean of its divisors is an integer number (85771168).

Almost surely, 2^665121361 is an apocalyptic number.

It is an amenable number.

665121361 is a deficient number, since it is larger than the sum of its proper divisors (21047983).

665121361 is a wasteful number, since it uses less digits than its factorization.

665121361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80871.

The product of its digits is 6480, while the sum is 31.

The square root of 665121361 is about 25789.9468979678. The cubic root of 665121361 is about 872.9049681215.

The spelling of 665121361 in words is "six hundred sixty-five million, one hundred twenty-one thousand, three hundred sixty-one".