81698727472 has 40 divisors (see below), whose sum is σ = 161322911280. Its totient is φ = 40067439360.

The previous prime is 81698727469. The next prime is 81698727491. The reversal of 81698727472 is 27472789618.

It is an alternating number because its digits alternate between even and odd.

It is a self number, because there is not a number n which added to its sum of digits gives 81698727472.

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 7 ways as a sum of consecutive naturals, for example, 3600322 + ... + 3622942.

It is an arithmetic number, because the mean of its divisors is an integer number (4033072782).

Almost surely, 2^81698727472 is an apocalyptic number.

It is an amenable number.

81698727472 is a deficient number, since it is larger than the sum of its proper divisors (79624183808).

81698727472 is a wasteful number, since it uses less digits than its factorization.

81698727472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26941 (or 26935 counting only the distinct ones).

The product of its digits is 18966528, while the sum is 61.

The spelling of 81698727472 in words is "eighty-one billion, six hundred ninety-eight million, seven hundred twenty-seven thousand, four hundred seventy-two".