81683433664 has 56 divisors (see below), whose sum is σ = 185383261440. Its totient is φ = 34981314816.

The previous prime is 81683433649. The next prime is 81683433673. The reversal of 81683433664 is 46633438618.

It is a tau number, because it is divible by the number of its divisors (56).

It is a hoax number, since the sum of its digits (52) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 545727 + ... + 679105.

Almost surely, 2^81683433664 is an apocalyptic number.

It is an amenable number.

81683433664 is an abundant number, since it is smaller than the sum of its proper divisors (103699827776).

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

81683433664 is a wasteful number, since it uses less digits than its factorization.

81683433664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134765 (or 134755 counting only the distinct ones).

The product of its digits is 5971968, while the sum is 52.

The spelling of 81683433664 in words is "eighty-one billion, six hundred eighty-three million, four hundred thirty-three thousand, six hundred sixty-four".