665611897 has 16 divisors (see below), whose sum is σ = 713603520. Its totient is φ = 618654208.

The previous prime is 665611871. The next prime is 665611939. The reversal of 665611897 is 798116566.

It is a happy number.

It is not a de Polignac number, because 665611897 - 2¹¹ = 665609849 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 665611897.

It is not an unprimeable number, because it can be changed into a prime (665611847) 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, 528054 + ... + 529312.

It is an arithmetic number, because the mean of its divisors is an integer number (44600220).

Almost surely, 2^665611897 is an apocalyptic number.

It is an amenable number.

665611897 is a deficient number, since it is larger than the sum of its proper divisors (47991623).

665611897 is a wasteful number, since it uses less digits than its factorization.

665611897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1640.

The product of its digits is 544320, while the sum is 49.

The square root of 665611897 is about 25799.4553624684. The cubic root of 665611897 is about 873.1195084616.

The spelling of 665611897 in words is "six hundred sixty-five million, six hundred eleven thousand, eight hundred ninety-seven".