665161619 has 4 divisors (see below), whose sum is σ = 674273496. Its totient is φ = 656049744.

The previous prime is 665161597. The next prime is 665161631. The reversal of 665161619 is 916161566.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 916161566 = 2 ⋅458080783.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665161619 is a prime.

It is a super-2 number, since 2×665161619² = 884879958781402322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665161649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4555829 + ... + 4555974.

It is an arithmetic number, because the mean of its divisors is an integer number (168568374).

Almost surely, 2^665161619 is an apocalyptic number.

665161619 is a deficient number, since it is larger than the sum of its proper divisors (9111877).

665161619 is an equidigital number, since it uses as much as digits as its factorization.

665161619 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9111876.

The product of its digits is 58320, while the sum is 41.

The square root of 665161619 is about 25790.7273840813. The cubic root of 665161619 is about 872.9225792931.

The spelling of 665161619 in words is "six hundred sixty-five million, one hundred sixty-one thousand, six hundred nineteen".