65815439813 has 2 divisors, whose sum is σ = 65815439814. Its totient is φ = 65815439812.

The previous prime is 65815439783. The next prime is 65815439821. The reversal of 65815439813 is 31893451856.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55075641124 + 10739798689 = 234682^2 + 103633^2 .

It is a cyclic number.

It is not a de Polignac number, because 65815439813 - 2¹² = 65815435717 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (65815439513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32907719906 + 32907719907.

It is an arithmetic number, because the mean of its divisors is an integer number (32907719907).

Almost surely, 2^65815439813 is an apocalyptic number.

It is an amenable number.

65815439813 is a deficient number, since it is larger than the sum of its proper divisors (1).

65815439813 is an equidigital number, since it uses as much as digits as its factorization.

65815439813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3110400, while the sum is 53.

The spelling of 65815439813 in words is "sixty-five billion, eight hundred fifteen million, four hundred thirty-nine thousand, eight hundred thirteen".