81966199898 has 16 divisors (see below), whose sum is σ = 134133995520. Its totient is φ = 37255284000.

The previous prime is 81966199877. The next prime is 81966199921. The reversal of 81966199898 is 89899166918.

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, 341543 + ... + 529701.

It is an arithmetic number, because the mean of its divisors is an integer number (8383374720).

Almost surely, 2^81966199898 is an apocalyptic number.

81966199898 is a deficient number, since it is larger than the sum of its proper divisors (52167795622).

81966199898 is a wasteful number, since it uses less digits than its factorization.

81966199898 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 207973.

The product of its digits is 120932352, while the sum is 74.

The spelling of 81966199898 in words is "eighty-one billion, nine hundred sixty-six million, one hundred ninety-nine thousand, eight hundred ninety-eight".