81683634984 has 128 divisors (see below), whose sum is σ = 235189094400. Its totient is φ = 23158160640.

The previous prime is 81683634983. The next prime is 81683635009. The reversal of 81683634984 is 48943638618.

It is not an unprimeable number, because it can be changed into a prime (81683634983) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11961379 + ... + 11968205.

It is an arithmetic number, because the mean of its divisors is an integer number (1837414800).

Almost surely, 2^81683634984 is an apocalyptic number.

81683634984 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81683634984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (117594547200).

81683634984 is an abundant number, since it is smaller than the sum of its proper divisors (153505459416).

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

81683634984 is a wasteful number, since it uses less digits than its factorization.

81683634984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7383 (or 7379 counting only the distinct ones).

The product of its digits is 23887872, while the sum is 60.

The spelling of 81683634984 in words is "eighty-one billion, six hundred eighty-three million, six hundred thirty-four thousand, nine hundred eighty-four".