3218686813 has 2 divisors, whose sum is σ = 3218686814. Its totient is φ = 3218686812.

The previous prime is 3218686763. The next prime is 3218686831. The reversal of 3218686813 is 3186868123.

Together with next prime (3218686831) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2125855449 + 1092831364 = 46107^2 + 33058^2 .

It is a cyclic number.

It is not a de Polignac number, because 3218686813 - 2²¹ = 3216589661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3218686843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1609343406 + 1609343407.

It is an arithmetic number, because the mean of its divisors is an integer number (1609343407).

Almost surely, 2^3218686813 is an apocalyptic number.

It is an amenable number.

3218686813 is a deficient number, since it is larger than the sum of its proper divisors (1).

3218686813 is an equidigital number, since it uses as much as digits as its factorization.

3218686813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 331776, while the sum is 46.

The square root of 3218686813 is about 56733.4717164391. The cubic root of 3218686813 is about 1476.4754842593.

The spelling of 3218686813 in words is "three billion, two hundred eighteen million, six hundred eighty-six thousand, eight hundred thirteen".