81735261749 has 2 divisors, whose sum is σ = 81735261750. Its totient is φ = 81735261748.

The previous prime is 81735261691. The next prime is 81735261779. The reversal of 81735261749 is 94716253718.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 67907148100 + 13828113649 = 260590^2 + 117593^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81735261749 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81735261749.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81735261779) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40867630874 + 40867630875.

It is an arithmetic number, because the mean of its divisors is an integer number (40867630875).

Almost surely, 2^81735261749 is an apocalyptic number.

It is an amenable number.

81735261749 is a deficient number, since it is larger than the sum of its proper divisors (1).

81735261749 is an equidigital number, since it uses as much as digits as its factorization.

81735261749 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2540160, while the sum is 53.

The spelling of 81735261749 in words is "eighty-one billion, seven hundred thirty-five million, two hundred sixty-one thousand, seven hundred forty-nine".