665372881 has 8 divisors (see below), whose sum is σ = 675633320. Its totient is φ = 655143552.

The previous prime is 665372867. The next prime is 665372909. The reversal of 665372881 is 188273566.

It can be written as a sum of positive squares in 4 ways, for example, as 4060225 + 661312656 = 2015^2 + 25716^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 665372881 - 2⁵ = 665372849 is a prime.

It is a super-2 number, since 2×665372881² = 885442141540480322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665372801) 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, 37315 + ... + 52183.

It is an arithmetic number, because the mean of its divisors is an integer number (84454165).

Almost surely, 2^665372881 is an apocalyptic number.

It is an amenable number.

665372881 is a deficient number, since it is larger than the sum of its proper divisors (10260439).

665372881 is a wasteful number, since it uses less digits than its factorization.

665372881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15555.

The product of its digits is 483840, while the sum is 46.

The square root of 665372881 is about 25794.8227557392. The cubic root of 665372881 is about 873.0149858322.

The spelling of 665372881 in words is "six hundred sixty-five million, three hundred seventy-two thousand, eight hundred eighty-one".