81303108781 has 2 divisors, whose sum is σ = 81303108782. Its totient is φ = 81303108780.

The previous prime is 81303108743. The next prime is 81303108797. The reversal of 81303108781 is 18780130318.

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., 75202092900 + 6101015881 = 274230^2 + 78109^2 .

It is a cyclic number.

It is not a de Polignac number, because 81303108781 - 2²¹ = 81301011629 is a prime.

It is a super-2 number, since 2×81303108781² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81303108701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40651554390 + 40651554391.

It is an arithmetic number, because the mean of its divisors is an integer number (40651554391).

Almost surely, 2^81303108781 is an apocalyptic number.

It is an amenable number.

81303108781 is a deficient number, since it is larger than the sum of its proper divisors (1).

81303108781 is an equidigital number, since it uses as much as digits as its factorization.

81303108781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32256, while the sum is 40.

The spelling of 81303108781 in words is "eighty-one billion, three hundred three million, one hundred eight thousand, seven hundred eighty-one".