81300013 has 2 divisors, whose sum is σ = 81300014. Its totient is φ = 81300012.

The previous prime is 81299983. The next prime is 81300017. The reversal of 81300013 is 31000318.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 74425129 + 6874884 = 8627^2 + 2622^2 .

It is a cyclic number.

It is not a de Polignac number, because 81300013 - 2⁹ = 81299501 is a prime.

It is a super-3 number, since 3×81300013³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a self number, because there is not a number n which added to its sum of digits gives 81300013.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81300017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40650006 + 40650007.

It is an arithmetic number, because the mean of its divisors is an integer number (40650007).

Almost surely, 2^81300013 is an apocalyptic number.

It is an amenable number.

81300013 is a deficient number, since it is larger than the sum of its proper divisors (1).

81300013 is an equidigital number, since it uses as much as digits as its factorization.

81300013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 81300013 is about 9016.6519839683. The cubic root of 81300013 is about 433.2084025787.

The spelling of 81300013 in words is "eighty-one million, three hundred thousand, thirteen".