665274919 has 4 divisors (see below), whose sum is σ = 667730080. Its totient is φ = 662819760.

The previous prime is 665274917. The next prime is 665274941. The reversal of 665274919 is 919472566.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 919472566 = 2 ⋅459736283.

It is a cyclic number.

It is not a de Polignac number, because 665274919 - 2¹ = 665274917 is a prime.

It is a super-3 number, since 3×665274919³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665274913) 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, 1227174 + ... + 1227715.

It is an arithmetic number, because the mean of its divisors is an integer number (166932520).

Almost surely, 2^665274919 is an apocalyptic number.

665274919 is a deficient number, since it is larger than the sum of its proper divisors (2455161).

665274919 is a wasteful number, since it uses less digits than its factorization.

665274919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2455160.

The product of its digits is 816480, while the sum is 49.

The square root of 665274919 is about 25792.9238164269. The cubic root of 665274919 is about 872.9721394353.

The spelling of 665274919 in words is "six hundred sixty-five million, two hundred seventy-four thousand, nine hundred nineteen".