81057073 has 2 divisors, whose sum is σ = 81057074. Its totient is φ = 81057072.

The previous prime is 81057023. The next prime is 81057103. The reversal of 81057073 is 37075018.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 76247824 + 4809249 = 8732^2 + 2193^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81057073 is a prime.

It is not a weakly prime, because it can be changed into another prime (81057023) 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, 40528536 + 40528537.

It is an arithmetic number, because the mean of its divisors is an integer number (40528537).

Almost surely, 2^81057073 is an apocalyptic number.

It is an amenable number.

81057073 is a deficient number, since it is larger than the sum of its proper divisors (1).

81057073 is an equidigital number, since it uses as much as digits as its factorization.

81057073 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5880, while the sum is 31.

The square root of 81057073 is about 9003.1701638923. The cubic root of 81057073 is about 432.7764688508.

The spelling of 81057073 in words is "eighty-one million, fifty-seven thousand, seventy-three".