81397090252800 has 5184 divisors, whose sum is σ = 374218098508800. Its totient is φ = 17457256857600.

The previous prime is 81397090252763. The next prime is 81397090252817. The reversal of 81397090252800 is 825209079318.

81397090252800 is a `hidden beast` number, since 81 + 39 + 7 + 0 + 9 + 0 + 2 + 528 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (5184).

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 pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 431 ways as a sum of consecutive naturals, for example, 1115028633564 + ... + 1115028633636.

It is an arithmetic number, because the mean of its divisors is an integer number (72187133200).

Almost surely, 2^{81397090252800} is an apocalyptic number.

81397090252800 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 81397090252800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (187109049254400).

81397090252800 is an abundant number, since it is smaller than the sum of its proper divisors (292821008256000).

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

81397090252800 is a wasteful number, since it uses less digits than its factorization.

81397090252800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 224 (or 180 counting only the distinct ones).

The product of its (nonzero) digits is 2177280, while the sum is 54.

The spelling of 81397090252800 in words is "eighty-one trillion, three hundred ninety-seven billion, ninety million, two hundred fifty-two thousand, eight hundred".