81259718400 has 1080 divisors, whose sum is σ = 351150615200. Its totient is φ = 18533007360.

The previous prime is 81259718389. The next prime is 81259718443. The reversal of 81259718400 is 481795218.

81259718400 is a `hidden beast` number, since 8 + 1 + 2 + 597 + 18 + 40 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1080).

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 polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 177810972 + ... + 177811428.

Almost surely, 2^81259718400 is an apocalyptic number.

81259718400 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 81259718400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (175575307600).

81259718400 is an abundant number, since it is smaller than the sum of its proper divisors (269890896800).

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

81259718400 is an equidigital number, since it uses as much as digits as its factorization.

81259718400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 516 (or 474 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 45.

The spelling of 81259718400 in words is "eighty-one billion, two hundred fifty-nine million, seven hundred eighteen thousand, four hundred".