81709420641480 has 144 divisors (see below), whose sum is σ = 272926775377620. Its totient is φ = 21200281984512.

The previous prime is 81709420641419. The next prime is 81709420641529. The reversal of 81709420641480 is 8414602490718.

81709420641480 is a `hidden beast` number, since 8 + 1 + 70 + 9 + 420 + 6 + 4 + 148 + 0 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 44215132106916 + 37494288534564 = 6649446^2 + 6123258^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 82403659 + ... + 83389338.

Almost surely, 2^{81709420641480} is an apocalyptic number.

It is an amenable number.

81709420641480 is an abundant number, since it is smaller than the sum of its proper divisors (191217354736140).

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

81709420641480 is a wasteful number, since it uses less digits than its factorization.

81709420641480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165793088 (or 165793044 counting only the distinct ones).

The product of its (nonzero) digits is 3096576, while the sum is 54.

The spelling of 81709420641480 in words is "eighty-one trillion, seven hundred nine billion, four hundred twenty million, six hundred forty-one thousand, four hundred eighty".