81005329 has 2 divisors, whose sum is σ = 81005330. Its totient is φ = 81005328.

The previous prime is 81005311. The next prime is 81005363. The reversal of 81005329 is 92350018.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81000000 + 5329 = 9000^2 + 73^2 .

It is a cyclic number.

It is not a de Polignac number, because 81005329 - 2¹¹ = 81003281 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81005297 and 81005306.

It is not a weakly prime, because it can be changed into another prime (81005369) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40502664 + 40502665.

It is an arithmetic number, because the mean of its divisors is an integer number (40502665).

Almost surely, 2^81005329 is an apocalyptic number.

It is an amenable number.

81005329 is a deficient number, since it is larger than the sum of its proper divisors (1).

81005329 is an equidigital number, since it uses as much as digits as its factorization.

81005329 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 81005329 is about 9000.2960506863. The cubic root of 81005329 is about 432.6843594619.

It can be divided in two parts, 8100 and 5329, that multiplied together give a square (43164900 = 6570²).

The spelling of 81005329 in words is "eighty-one million, five thousand, three hundred twenty-nine".