81698180292 has 18 divisors (see below), whose sum is σ = 206514844718. Its totient is φ = 27232726752.

The previous prime is 81698180273. The next prime is 81698180309. The reversal of 81698180292 is 29208189618.

It can be written as a sum of positive squares in only one way, i.e., 61869597696 + 19828582596 = 248736^2 + 140814^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1134696913 + ... + 1134696984.

Almost surely, 2^81698180292 is an apocalyptic number.

It is an amenable number.

81698180292 is an abundant number, since it is smaller than the sum of its proper divisors (124816664426).

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

81698180292 is a wasteful number, since it uses less digits than its factorization.

81698180292 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2269393907 (or 2269393902 counting only the distinct ones).

The product of its (nonzero) digits is 995328, while the sum is 54.

The spelling of 81698180292 in words is "eighty-one billion, six hundred ninety-eight million, one hundred eighty thousand, two hundred ninety-two".