81219119066 has 4 divisors (see below), whose sum is σ = 121828678602. Its totient is φ = 40609559532.

The previous prime is 81219119057. The next prime is 81219119071. The reversal of 81219119066 is 66091191218.

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

It can be written as a sum of positive squares in only one way, i.e., 74903479225 + 6315639841 = 273685^2 + 79471^2 .

It is a Curzon number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 20304779765 + ... + 20304779768.

Almost surely, 2^81219119066 is an apocalyptic number.

81219119066 is a deficient number, since it is larger than the sum of its proper divisors (40609559536).

81219119066 is a wasteful number, since it uses less digits than its factorization.

81219119066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40609559535.

The product of its (nonzero) digits is 46656, while the sum is 44.

The spelling of 81219119066 in words is "eighty-one billion, two hundred nineteen million, one hundred nineteen thousand, sixty-six".