81570543 has 4 divisors (see below), whose sum is σ = 108760728. Its totient is φ = 54380360.

The previous prime is 81570493. The next prime is 81570563. The reversal of 81570543 is 34507518.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81570543 - 2¹² = 81566447 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81570563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13595088 + ... + 13595093.

It is an arithmetic number, because the mean of its divisors is an integer number (27190182).

Almost surely, 2^81570543 is an apocalyptic number.

81570543 is a deficient number, since it is larger than the sum of its proper divisors (27190185).

81570543 is a wasteful number, since it uses less digits than its factorization.

81570543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27190184.

The product of its (nonzero) digits is 16800, while the sum is 33.

The square root of 81570543 is about 9031.6412129801. The cubic root of 81570543 is about 433.6883783821.

The spelling of 81570543 in words is "eighty-one million, five hundred seventy thousand, five hundred forty-three".