81288282320 has 160 divisors (see below), whose sum is σ = 218381522688. Its totient is φ = 27563986944.

The previous prime is 81288282307. The next prime is 81288282389. The reversal of 81288282320 is 2328288218.

It is a Cunningham number, because it is equal to 285111²-1.

It is a super-3 number, since 3×81288282320³ (a number of 34 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19955804 + ... + 19959876.

Almost surely, 2^81288282320 is an apocalyptic number.

81288282320 is a gapful number since it is divisible by the number (80) 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 81288282320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109190761344).

81288282320 is an abundant number, since it is smaller than the sum of its proper divisors (137093240368).

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

81288282320 is a wasteful number, since it uses less digits than its factorization.

81288282320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4477 (or 4471 counting only the distinct ones).

The product of its (nonzero) digits is 196608, while the sum is 44.

The spelling of 81288282320 in words is "eighty-one billion, two hundred eighty-eight million, two hundred eighty-two thousand, three hundred twenty".