81982817280 has 1760 divisors, whose sum is σ = 385301078400. Its totient is φ = 16387080192.

The previous prime is 81982817221. The next prime is 81982817281. The reversal of 81982817280 is 8271828918.

81982817280 is a `hidden beast` number, since 81 + 9 + 8 + 281 + 7 + 280 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81982817281) by changing a digit.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 4314885111 + ... + 4314885129.

Almost surely, 2^81982817280 is an apocalyptic number.

81982817280 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 81982817280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (192650539200).

81982817280 is an abundant number, since it is smaller than the sum of its proper divisors (303318261120).

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

81982817280 is a wasteful number, since it uses less digits than its factorization.

81982817280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94 (or 49 counting only the distinct ones).

The product of its (nonzero) digits is 1032192, while the sum is 54.

The spelling of 81982817280 in words is "eighty-one billion, nine hundred eighty-two million, eight hundred seventeen thousand, two hundred eighty".