81312422400 has 960 divisors, whose sum is σ = 331175053440. Its totient is φ = 19375718400.

The previous prime is 81312422329. The next prime is 81312422413. The reversal of 81312422400 is 422421318.

81312422400 is a `hidden beast` number, since 8 + 13 + 1 + 242 + 2 + 400 = 666.

It is a tau number, because it is divible by the number of its divisors (960).

It is a super-2 number, since 2×81312422400² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 277516654 + ... + 277516946.

It is an arithmetic number, because the mean of its divisors is an integer number (344974014).

Almost surely, 2^81312422400 is an apocalyptic number.

81312422400 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 81312422400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (165587526720).

81312422400 is an abundant number, since it is smaller than the sum of its proper divisors (249862631040).

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

81312422400 is a wasteful number, since it uses less digits than its factorization.

81312422400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 414 (or 387 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

Adding to 81312422400 its reverse (422421318), we get a palindrome (81734843718).

The spelling of 81312422400 in words is "eighty-one billion, three hundred twelve million, four hundred twenty-two thousand, four hundred".