81011543611 has 4 divisors (see below), whose sum is σ = 81038186424. Its totient is φ = 80984900800.

The previous prime is 81011543597. The next prime is 81011543653. The reversal of 81011543611 is 11634511018.

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 81011543611 - 2⁹ = 81011543099 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81011543111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13316845 + ... + 13322926.

It is an arithmetic number, because the mean of its divisors is an integer number (20259546606).

Almost surely, 2^81011543611 is an apocalyptic number.

81011543611 is a deficient number, since it is larger than the sum of its proper divisors (26642813).

81011543611 is a wasteful number, since it uses less digits than its factorization.

81011543611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26642812.

The product of its (nonzero) digits is 2880, while the sum is 31.

The spelling of 81011543611 in words is "eighty-one billion, eleven million, five hundred forty-three thousand, six hundred eleven".