81688285512 has 96 divisors (see below), whose sum is σ = 241508685600. Its totient is φ = 25796289024.

The previous prime is 81688285489. The next prime is 81688285517. The reversal of 81688285512 is 21558288618.

81688285512 is a `hidden beast` number, since 8 + 1 + 6 + 8 + 82 + 8 + 551 + 2 = 666.

It is a super-3 number, since 3×81688285512³ (a number of 34 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (81688285517) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1068873 + ... + 1142744.

It is an arithmetic number, because the mean of its divisors is an integer number (2515715475).

Almost surely, 2^81688285512 is an apocalyptic number.

It is an amenable number.

81688285512 is an abundant number, since it is smaller than the sum of its proper divisors (159820400088).

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

81688285512 is a wasteful number, since it uses less digits than its factorization.

81688285512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2211657 (or 2211641 counting only the distinct ones).

The product of its digits is 2457600, while the sum is 54.

The spelling of 81688285512 in words is "eighty-one billion, six hundred eighty-eight million, two hundred eighty-five thousand, five hundred twelve".