81718845120 has 336 divisors, whose sum is σ = 307855181088. Its totient is φ = 19731578880.

The previous prime is 81718845101. The next prime is 81718845157. The reversal of 81718845120 is 2154881718.

81718845120 is a `hidden beast` number, since 8 + 17 + 188 + 451 + 2 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 8136742 + ... + 8146778.

It is an arithmetic number, because the mean of its divisors is an integer number (916235658).

Almost surely, 2^81718845120 is an apocalyptic number.

81718845120 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 81718845120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (153927590544).

81718845120 is an abundant number, since it is smaller than the sum of its proper divisors (226136335968).

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

81718845120 is a wasteful number, since it uses less digits than its factorization.

81718845120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10328 (or 10315 counting only the distinct ones).

The product of its (nonzero) digits is 143360, while the sum is 45.

The spelling of 81718845120 in words is "eighty-one billion, seven hundred eighteen million, eight hundred forty-five thousand, one hundred twenty".