81529543 has 2 divisors, whose sum is σ = 81529544. Its totient is φ = 81529542.

The previous prime is 81529531. The next prime is 81529559. The reversal of 81529543 is 34592518.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81529543 - 2²¹ = 79432391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81529243) 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, 40764771 + 40764772.

It is an arithmetic number, because the mean of its divisors is an integer number (40764772).

Almost surely, 2^81529543 is an apocalyptic number.

81529543 is a deficient number, since it is larger than the sum of its proper divisors (1).

81529543 is an equidigital number, since it uses as much as digits as its factorization.

81529543 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 43200, while the sum is 37.

The square root of 81529543 is about 9029.3711298185. The cubic root of 81529543 is about 433.6157042572.

The spelling of 81529543 in words is "eighty-one million, five hundred twenty-nine thousand, five hundred forty-three".