665274795681 has 4 divisors (see below), whose sum is σ = 887033060912. Its totient is φ = 443516530452.

The previous prime is 665274795667. The next prime is 665274795701. The reversal of 665274795681 is 186597472566.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 665274795681 - 2⁹ = 665274795169 is a prime.

It is a super-3 number, since 3×665274795681³ (a number of 36 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665274795631) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 110879132611 + ... + 110879132616.

It is an arithmetic number, because the mean of its divisors is an integer number (221758265228).

Almost surely, 2^665274795681 is an apocalyptic number.

It is an amenable number.

665274795681 is a deficient number, since it is larger than the sum of its proper divisors (221758265231).

665274795681 is a wasteful number, since it uses less digits than its factorization.

665274795681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221758265230.

The product of its digits is 152409600, while the sum is 66.

The spelling of 665274795681 in words is "six hundred sixty-five billion, two hundred seventy-four million, seven hundred ninety-five thousand, six hundred eighty-one".