81738593749 has 2 divisors, whose sum is σ = 81738593750. Its totient is φ = 81738593748.

The previous prime is 81738593683. The next prime is 81738593801. The reversal of 81738593749 is 94739583718.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 54013013649 + 27725580100 = 232407^2 + 166510^2 .

It is a cyclic number.

It is not a de Polignac number, because 81738593749 - 2³¹ = 79591110101 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81738593449) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40869296874 + 40869296875.

It is an arithmetic number, because the mean of its divisors is an integer number (40869296875).

Almost surely, 2^81738593749 is an apocalyptic number.

It is an amenable number.

81738593749 is a deficient number, since it is larger than the sum of its proper divisors (1).

81738593749 is an equidigital number, since it uses as much as digits as its factorization.

81738593749 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 45722880, while the sum is 64.

The spelling of 81738593749 in words is "eighty-one billion, seven hundred thirty-eight million, five hundred ninety-three thousand, seven hundred forty-nine".