81071057 has 2 divisors, whose sum is σ = 81071058. Its totient is φ = 81071056.

The previous prime is 81071017. The next prime is 81071071. The reversal of 81071057 is 75017018.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80712256 + 358801 = 8984^2 + 599^2 .

It is a cyclic number.

It is not a de Polignac number, because 81071057 - 2²² = 76876753 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81071017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40535528 + 40535529.

It is an arithmetic number, because the mean of its divisors is an integer number (40535529).

Almost surely, 2^81071057 is an apocalyptic number.

It is an amenable number.

81071057 is a deficient number, since it is larger than the sum of its proper divisors (1).

81071057 is an equidigital number, since it uses as much as digits as its factorization.

81071057 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1960, while the sum is 29.

The square root of 81071057 is about 9003.9467457332. The cubic root of 81071057 is about 432.8013550120.

The spelling of 81071057 in words is "eighty-one million, seventy-one thousand, fifty-seven".