81408733540 has 12 divisors (see below), whose sum is σ = 170958340476. Its totient is φ = 32563493408.

The previous prime is 81408733531. The next prime is 81408733559. The reversal of 81408733540 is 4533780418.

It can be written as a sum of positive squares in 2 ways, for example, as 48182006016 + 33226727524 = 219504^2 + 182282^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2035218319 + ... + 2035218358.

It is an arithmetic number, because the mean of its divisors is an integer number (14246528373).

Almost surely, 2^81408733540 is an apocalyptic number.

It is an amenable number.

81408733540 is an abundant number, since it is smaller than the sum of its proper divisors (89549606936).

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

81408733540 is a wasteful number, since it uses less digits than its factorization.

81408733540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4070436686 (or 4070436684 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 43.

The spelling of 81408733540 in words is "eighty-one billion, four hundred eight million, seven hundred thirty-three thousand, five hundred forty".