81028081913 has 2 divisors, whose sum is σ = 81028081914. Its totient is φ = 81028081912.

The previous prime is 81028081907. The next prime is 81028081931. The reversal of 81028081913 is 31918082018.

Together with next prime (81028081931) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 56186539369 + 24841542544 = 237037^2 + 157612^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81028081913 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (81028021913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40514040956 + 40514040957.

It is an arithmetic number, because the mean of its divisors is an integer number (40514040957).

Almost surely, 2^81028081913 is an apocalyptic number.

It is an amenable number.

81028081913 is a deficient number, since it is larger than the sum of its proper divisors (1).

81028081913 is an equidigital number, since it uses as much as digits as its factorization.

81028081913 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27648, while the sum is 41.

The spelling of 81028081913 in words is "eighty-one billion, twenty-eight million, eighty-one thousand, nine hundred thirteen".