81375781696 has 224 divisors, whose sum is σ = 194065818624. Its totient is φ = 33423360000.

The previous prime is 81375781681. The next prime is 81375781723. The reversal of 81375781696 is 69618757318.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 50827296 + ... + 50828896.

Almost surely, 2^81375781696 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81375781696, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97032909312).

81375781696 is an abundant number, since it is smaller than the sum of its proper divisors (112690036928).

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

81375781696 is a wasteful number, since it uses less digits than its factorization.

81375781696 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1809 (or 1799 counting only the distinct ones).

The product of its digits is 15240960, while the sum is 61.

The spelling of 81375781696 in words is "eighty-one billion, three hundred seventy-five million, seven hundred eighty-one thousand, six hundred ninety-six".