81368133013 has 2 divisors, whose sum is σ = 81368133014. Its totient is φ = 81368133012.

The previous prime is 81368132983. The next prime is 81368133043. The reversal of 81368133013 is 31033186318.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (81368132983) and next prime (81368133043).

It can be written as a sum of positive squares in only one way, i.e., 49942416484 + 31425716529 = 223478^2 + 177273^2 .

It is a cyclic number.

It is not a de Polignac number, because 81368133013 - 2¹³ = 81368124821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81368133043) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40684066506 + 40684066507.

It is an arithmetic number, because the mean of its divisors is an integer number (40684066507).

Almost surely, 2^81368133013 is an apocalyptic number.

It is an amenable number.

81368133013 is a deficient number, since it is larger than the sum of its proper divisors (1).

81368133013 is an equidigital number, since it uses as much as digits as its factorization.

81368133013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 31104, while the sum is 37.

The spelling of 81368133013 in words is "eighty-one billion, three hundred sixty-eight million, one hundred thirty-three thousand, thirteen".