3116821 has 4 divisors (see below), whose sum is σ = 3124044. Its totient is φ = 3109600.

The previous prime is 3116819. The next prime is 3116837. The reversal of 3116821 is 1286113.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1286113 = 557 ⋅2309.

It can be written as a sum of positive squares in 2 ways, for example, as 1768900 + 1347921 = 1330^2 + 1161^2 .

It is a cyclic number.

It is not a de Polignac number, because 3116821 - 2¹ = 3116819 is a prime.

It is a Duffinian number.

3116821 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 3116792 and 3116801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3116851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2920 + ... + 3841.

It is an arithmetic number, because the mean of its divisors is an integer number (781011).

Almost surely, 2^3116821 is an apocalyptic number.

It is an amenable number.

3116821 is a deficient number, since it is larger than the sum of its proper divisors (7223).

3116821 is an equidigital number, since it uses as much as digits as its factorization.

3116821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7222.

The product of its digits is 288, while the sum is 22.

The square root of 3116821 is about 1765.4520667523. The cubic root of 3116821 is about 146.0732259185.

The spelling of 3116821 in words is "three million, one hundred sixteen thousand, eight hundred twenty-one".