81139017772800 has 3240 divisors, whose sum is σ = 347158569398256. Its totient is φ = 18624259031040.

The previous prime is 81139017772753. The next prime is 81139017772823. The reversal of 81139017772800 is 827771093118.

81139017772800 is a `hidden beast` number, since 8 + 1 + 1 + 390 + 177 + 7 + 2 + 80 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (3240).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 359 ways as a sum of consecutive naturals, for example, 233830022227 + ... + 233830022573.

Almost surely, 2^{81139017772800} is an apocalyptic number.

81139017772800 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 81139017772800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (173579284699128).

81139017772800 is an abundant number, since it is smaller than the sum of its proper divisors (266019551625456).

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

81139017772800 is a wasteful number, since it uses less digits than its factorization.

81139017772800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 585 (or 544 counting only the distinct ones).

The product of its (nonzero) digits is 1185408, while the sum is 54.

The spelling of 81139017772800 in words is "eighty-one trillion, one hundred thirty-nine billion, seventeen million, seven hundred seventy-two thousand, eight hundred".