81896782688 has 144 divisors (see below), whose sum is σ = 191516648400. Its totient is φ = 34363284480.

The previous prime is 81896782687. The next prime is 81896782703. The reversal of 81896782688 is 88628769818.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81896782687) 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, 21901523 + ... + 21905261.

It is an arithmetic number, because the mean of its divisors is an integer number (1329976725).

Almost surely, 2^81896782688 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 81896782688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (95758324200).

81896782688 is an abundant number, since it is smaller than the sum of its proper divisors (109619865712).

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

81896782688 is a wasteful number, since it uses less digits than its factorization.

81896782688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4053 (or 4038 counting only the distinct ones).

The product of its digits is 148635648, while the sum is 71.

The spelling of 81896782688 in words is "eighty-one billion, eight hundred ninety-six million, seven hundred eighty-two thousand, six hundred eighty-eight".