2665817813 has 4 divisors (see below), whose sum is σ = 2751811968. Its totient is φ = 2579823660.

The previous prime is 2665817789. The next prime is 2665817831. The reversal of 2665817813 is 3187185662.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 3187185662 = 2 ⋅1593592831.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2665817813 is a prime.

It is a super-2 number, since 2×2665817813² = 14213169224216205938, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2665817113) 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, 42997031 + ... + 42997092.

It is an arithmetic number, because the mean of its divisors is an integer number (687952992).

Almost surely, 2^2665817813 is an apocalyptic number.

It is an amenable number.

2665817813 is a deficient number, since it is larger than the sum of its proper divisors (85994155).

2665817813 is an equidigital number, since it uses as much as digits as its factorization.

2665817813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85994154.

The product of its digits is 483840, while the sum is 47.

The square root of 2665817813 is about 51631.5583049747. The cubic root of 2665817813 is about 1386.5753925209.

The spelling of 2665817813 in words is "two billion, six hundred sixty-five million, eight hundred seventeen thousand, eight hundred thirteen".