665248993 has 4 divisors (see below), whose sum is σ = 665535508. Its totient is φ = 664962480.

The previous prime is 665248979. The next prime is 665248999. The reversal of 665248993 is 399842566.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 399842566 = 2 ⋅199921283.

It can be written as a sum of positive squares in 2 ways, for example, as 337530384 + 327718609 = 18372^2 + 18103^2 .

It is a cyclic number.

It is not a de Polignac number, because 665248993 - 2¹³ = 665240801 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 665248993.

It is not an unprimeable number, because it can be changed into a prime (665248999) 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, 139746 + ... + 144427.

It is an arithmetic number, because the mean of its divisors is an integer number (166383877).

Almost surely, 2^665248993 is an apocalyptic number.

It is an amenable number.

665248993 is a deficient number, since it is larger than the sum of its proper divisors (286515).

665248993 is a wasteful number, since it uses less digits than its factorization.

665248993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 286514.

The product of its digits is 2799360, while the sum is 52.

The square root of 665248993 is about 25792.4212318270. The cubic root of 665248993 is about 872.9607992765.

The spelling of 665248993 in words is "six hundred sixty-five million, two hundred forty-eight thousand, nine hundred ninety-three".