81787786080 has 2304 divisors, whose sum is σ = 399272509440. Its totient is φ = 13536460800.

The previous prime is 81787786057. The next prime is 81787786127. The reversal of 81787786080 is 8068778718.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (60).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 2638315665 + ... + 2638315695.

It is an arithmetic number, because the mean of its divisors is an integer number (173295360).

Almost surely, 2^81787786080 is an apocalyptic number.

81787786080 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 81787786080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (199636254720).

81787786080 is an abundant number, since it is smaller than the sum of its proper divisors (317484723360).

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

81787786080 is a wasteful number, since it uses less digits than its factorization.

81787786080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133 (or 108 counting only the distinct ones).

The product of its (nonzero) digits is 8429568, while the sum is 60.

The spelling of 81787786080 in words is "eighty-one billion, seven hundred eighty-seven million, seven hundred eighty-six thousand, eighty".