81983778706 has 8 divisors (see below), whose sum is σ = 130209530940. Its totient is φ = 38580601728.

The previous prime is 81983778683. The next prime is 81983778727. The reversal of 81983778706 is 60787738918.

It can be written as a sum of positive squares in 2 ways, for example, as 70097328081 + 11886450625 = 264759^2 + 109025^2 .

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

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 in 3 ways as a sum of consecutive naturals, for example, 1205643771 + ... + 1205643838.

Almost surely, 2^81983778706 is an apocalyptic number.

81983778706 is a deficient number, since it is larger than the sum of its proper divisors (48225752234).

81983778706 is a wasteful number, since it uses less digits than its factorization.

81983778706 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2411287628.

The product of its (nonzero) digits is 28449792, while the sum is 64.

The spelling of 81983778706 in words is "eighty-one billion, nine hundred eighty-three million, seven hundred seventy-eight thousand, seven hundred six".