81811563242 has 8 divisors (see below), whose sum is σ = 125571236736. Its totient is φ = 39954484332.

The previous prime is 81811563227. The next prime is 81811563263. The reversal of 81811563242 is 24236511818.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 81811563242.

It is an unprimeable number.

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, 475648538 + ... + 475648709.

It is an arithmetic number, because the mean of its divisors is an integer number (15696404592).

Almost surely, 2^81811563242 is an apocalyptic number.

81811563242 is a deficient number, since it is larger than the sum of its proper divisors (43759673494).

81811563242 is a wasteful number, since it uses less digits than its factorization.

81811563242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 951297292.

The product of its digits is 92160, while the sum is 41.

The spelling of 81811563242 in words is "eighty-one billion, eight hundred eleven million, five hundred sixty-three thousand, two hundred forty-two".