81728654136 has 32 divisors (see below), whose sum is σ = 205881350400. Its totient is φ = 27034922720.

The previous prime is 81728654041. The next prime is 81728654149. The reversal of 81728654136 is 63145682718.

It is a hoax number, since the sum of its digits (51) 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 polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12994416 + ... + 13000703.

It is an arithmetic number, because the mean of its divisors is an integer number (6433792200).

Almost surely, 2^81728654136 is an apocalyptic number.

It is an amenable number.

81728654136 is an abundant number, since it is smaller than the sum of its proper divisors (124152696264).

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

81728654136 is a wasteful number, since it uses less digits than its factorization.

81728654136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25995259 (or 25995255 counting only the distinct ones).

The product of its digits is 1935360, while the sum is 51.

The spelling of 81728654136 in words is "eighty-one billion, seven hundred twenty-eight million, six hundred fifty-four thousand, one hundred thirty-six".