665925281 has 16 divisors (see below), whose sum is σ = 818165760. Its totient is φ = 529241040.

The previous prime is 665925263. The next prime is 665925283. The reversal of 665925281 is 182529566.

665925281 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 665925281 - 2⁶ = 665925217 is a prime.

It is a super-2 number, since 2×665925281² = 886912959749857922, which contains 22 as substring.

It is a Smith number, since the sum of its digits (44) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (665925283) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47015 + ... + 59516.

It is an arithmetic number, because the mean of its divisors is an integer number (51135360).

Almost surely, 2^665925281 is an apocalyptic number.

It is an amenable number.

665925281 is a deficient number, since it is larger than the sum of its proper divisors (152240479).

665925281 is a wasteful number, since it uses less digits than its factorization.

665925281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106604.

The product of its digits is 259200, while the sum is 44.

The square root of 665925281 is about 25805.5281093025. The cubic root of 665925281 is about 873.2565146030.

The spelling of 665925281 in words is "six hundred sixty-five million, nine hundred twenty-five thousand, two hundred eighty-one".