81144806400 has 1056 divisors, whose sum is σ = 352191426560. Its totient is φ = 17915904000.

The previous prime is 81144806389. The next prime is 81144806401. The reversal of 81144806400 is 460844118.

81144806400 is a `hidden beast` number, since 8 + 1 + 1 + 4 + 4 + 8 + 0 + 640 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81144806401) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 149990130 + ... + 149990670.

Almost surely, 2^81144806400 is an apocalyptic number.

81144806400 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 81144806400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (176095713280).

81144806400 is an abundant number, since it is smaller than the sum of its proper divisors (271046620160).

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

81144806400 is a wasteful number, since it uses less digits than its factorization.

81144806400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 618 (or 589 counting only the distinct ones).

The product of its (nonzero) digits is 24576, while the sum is 36.

The spelling of 81144806400 in words is "eighty-one billion, one hundred forty-four million, eight hundred six thousand, four hundred".