81744296639 has 2 divisors, whose sum is σ = 81744296640. Its totient is φ = 81744296638.

The previous prime is 81744296617. The next prime is 81744296671. The reversal of 81744296639 is 93669244718.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81744296639 - 2¹⁶ = 81744231103 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81744296939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40872148319 + 40872148320.

It is an arithmetic number, because the mean of its divisors is an integer number (40872148320).

Almost surely, 2^81744296639 is an apocalyptic number.

81744296639 is a deficient number, since it is larger than the sum of its proper divisors (1).

81744296639 is an equidigital number, since it uses as much as digits as its factorization.

81744296639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15676416, while the sum is 59.

The spelling of 81744296639 in words is "eighty-one billion, seven hundred forty-four million, two hundred ninety-six thousand, six hundred thirty-nine".