81116996400 has 1050 divisors, whose sum is σ = 338325143300. Its totient is φ = 18629740800.

The previous prime is 81116996383. The next prime is 81116996437. The reversal of 81116996400 is 469961118.

81116996400 is a `hidden beast` number, since 81 + 1 + 169 + 9 + 6 + 400 = 666.

It is a super-2 number, since 2×81116996400² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 209 ways as a sum of consecutive naturals, for example, 4269315591 + ... + 4269315609.

Almost surely, 2^81116996400 is an apocalyptic number.

81116996400 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 81116996400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (169162571650).

81116996400 is an abundant number, since it is smaller than the sum of its proper divisors (257208146900).

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

81116996400 is an equidigital number, since it uses as much as digits as its factorization.

81116996400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99 (or 40 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 45.

The spelling of 81116996400 in words is "eighty-one billion, one hundred sixteen million, nine hundred ninety-six thousand, four hundred".