81799699818 has 16 divisors (see below), whose sum is σ = 165219196896. Its totient is φ = 26996600400.

The previous prime is 81799699771. The next prime is 81799699823. The reversal of 81799699818 is 81899699718.

It is a self number, because there is not a number n which added to its sum of digits gives 81799699818.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 67490896 + ... + 67492107.

It is an arithmetic number, because the mean of its divisors is an integer number (10326199806).

Almost surely, 2^81799699818 is an apocalyptic number.

81799699818 is an abundant number, since it is smaller than the sum of its proper divisors (83419497078).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81799699818 is a wasteful number, since it uses less digits than its factorization.

81799699818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134983109.

The product of its digits is 141087744, while the sum is 75.

The spelling of 81799699818 in words is "eighty-one billion, seven hundred ninety-nine million, six hundred ninety-nine thousand, eight hundred eighteen".