81123456000 has 704 divisors, whose sum is σ = 293376695040. Its totient is φ = 19886899200.

The previous prime is 81123455989. The next prime is 81123456023. The reversal of 81123456000 is 65432118.

It is a super-2 number, since 2×81123456000² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1886591979 + ... + 1886592021.

It is an arithmetic number, because the mean of its divisors is an integer number (416728260).

Almost surely, 2^81123456000 is an apocalyptic number.

81123456000 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 81123456000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (146688347520).

81123456000 is an abundant number, since it is smaller than the sum of its proper divisors (212253239040).

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

81123456000 is an equidigital number, since it uses as much as digits as its factorization.

81123456000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132 (or 70 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 30.

Adding to 81123456000 its reverse (65432118), we get a palindrome (81188888118).

The spelling of 81123456000 in words is "eighty-one billion, one hundred twenty-three million, four hundred fifty-six thousand".