81288909140 has 12 divisors (see below), whose sum is σ = 170706709236. Its totient is φ = 32515563648.

The previous prime is 81288909089. The next prime is 81288909151. The reversal of 81288909140 is 4190988218.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 62022913936 + 19265995204 = 249044^2 + 138802^2 .

It is a hoax number, since the sum of its digits (50) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 2032222709 + ... + 2032222748.

It is an arithmetic number, because the mean of its divisors is an integer number (14225559103).

Almost surely, 2^81288909140 is an apocalyptic number.

It is an amenable number.

81288909140 is an abundant number, since it is smaller than the sum of its proper divisors (89417800096).

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

81288909140 is a wasteful number, since it uses less digits than its factorization.

81288909140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4064445466 (or 4064445464 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 50.

The spelling of 81288909140 in words is "eighty-one billion, two hundred eighty-eight million, nine hundred nine thousand, one hundred forty".