81025781760 has 1248 divisors, whose sum is σ = 363947754240. Its totient is φ = 16739205120.

The previous prime is 81025781747. The next prime is 81025781777. The reversal of 81025781760 is 6718752018.

It is a happy number.

81025781760 is a `hidden beast` number, since 8 + 1 + 0 + 2 + 578 + 1 + 76 + 0 = 666.

It is a super-3 number, since 3×81025781760³ (a number of 34 digits) contains 333 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 468357034 + ... + 468357206.

Almost surely, 2^81025781760 is an apocalyptic number.

81025781760 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 81025781760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (181973877120).

81025781760 is an abundant number, since it is smaller than the sum of its proper divisors (282921972480).

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

81025781760 is a wasteful number, since it uses less digits than its factorization.

81025781760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240 (or 201 counting only the distinct ones).

The product of its (nonzero) digits is 188160, while the sum is 45.

The spelling of 81025781760 in words is "eighty-one billion, twenty-five million, seven hundred eighty-one thousand, seven hundred sixty".