81812995140 has 24 divisors (see below), whose sum is σ = 229076386560. Its totient is φ = 21816798688.

The previous prime is 81812995111. The next prime is 81812995151. The reversal of 81812995140 is 4159921818.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 81812995140.

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, 681774900 + ... + 681775019.

It is an arithmetic number, because the mean of its divisors is an integer number (9544849440).

Almost surely, 2^81812995140 is an apocalyptic number.

It is an amenable number.

81812995140 is an abundant number, since it is smaller than the sum of its proper divisors (147263391420).

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

81812995140 is a wasteful number, since it uses less digits than its factorization.

81812995140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1363549931 (or 1363549929 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 48.

The spelling of 81812995140 in words is "eighty-one billion, eight hundred twelve million, nine hundred ninety-five thousand, one hundred forty".