81181782880 has 192 divisors, whose sum is σ = 215404842240. Its totient is φ = 28653004800.

The previous prime is 81181782833. The next prime is 81181782901. The reversal of 81181782880 is 8828718118.

It is a happy number.

It is a super-2 number, since 2×81181782880² (a number of 23 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (52) coincides with the sum of the digits of its distinct prime factors.

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, 31972651 + ... + 31975189.

It is an arithmetic number, because the mean of its divisors is an integer number (1121900220).

Almost surely, 2^81181782880 is an apocalyptic number.

81181782880 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 81181782880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107702421120).

81181782880 is an abundant number, since it is smaller than the sum of its proper divisors (134223059360).

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

81181782880 is a wasteful number, since it uses less digits than its factorization.

81181782880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3093 (or 3085 counting only the distinct ones).

The product of its (nonzero) digits is 458752, while the sum is 52.

The spelling of 81181782880 in words is "eighty-one billion, one hundred eighty-one million, seven hundred eighty-two thousand, eight hundred eighty".