81528113 has 2 divisors, whose sum is σ = 81528114. Its totient is φ = 81528112.

The previous prime is 81528103. The next prime is 81528119. The reversal of 81528113 is 31182518.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 68939809 + 12588304 = 8303^2 + 3548^2 .

It is a cyclic number.

It is not a de Polignac number, because 81528113 - 2²⁰ = 80479537 is a prime.

It is not a weakly prime, because it can be changed into another prime (81528119) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40764056 + 40764057.

It is an arithmetic number, because the mean of its divisors is an integer number (40764057).

Almost surely, 2^81528113 is an apocalyptic number.

It is an amenable number.

81528113 is a deficient number, since it is larger than the sum of its proper divisors (1).

81528113 is an equidigital number, since it uses as much as digits as its factorization.

81528113 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1920, while the sum is 29.

The square root of 81528113 is about 9029.2919434472. The cubic root of 81528113 is about 433.6131690859.

Subtracting from 81528113 its reverse (31182518), we obtain a triangular number (50345595 = T₁₀₀₃₄).

The spelling of 81528113 in words is "eighty-one million, five hundred twenty-eight thousand, one hundred thirteen".