81705378527 has 2 divisors, whose sum is σ = 81705378528. Its totient is φ = 81705378526.

The previous prime is 81705378493. The next prime is 81705378593. The reversal of 81705378527 is 72587350718.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81705378527 - 2¹⁰ = 81705377503 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81705372527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40852689263 + 40852689264.

It is an arithmetic number, because the mean of its divisors is an integer number (40852689264).

Almost surely, 2^81705378527 is an apocalyptic number.

81705378527 is a deficient number, since it is larger than the sum of its proper divisors (1).

81705378527 is an equidigital number, since it uses as much as digits as its factorization.

81705378527 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3292800, while the sum is 53.

The spelling of 81705378527 in words is "eighty-one billion, seven hundred five million, three hundred seventy-eight thousand, five hundred twenty-seven".