81441744400 has 135 divisors (see below), whose sum is σ = 206779228173. Its totient is φ = 30821040000.

The previous prime is 81441744389. The next prime is 81441744437. The reversal of 81441744400 is 444714418.

The square root of 81441744400 is 285380.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 29319027984 + 52122716416 = 171228^2 + 228304^2 .

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81441744400.

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 26 ways as a sum of consecutive naturals, for example, 108444025 + ... + 108444775.

Almost surely, 2^81441744400 is an apocalyptic number.

81441744400 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

81441744400 is the 285380-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81441744400

81441744400 is an abundant number, since it is smaller than the sum of its proper divisors (125337483773).

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

81441744400 is an equidigital number, since it uses as much as digits as its factorization.

81441744400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1558 (or 777 counting only the distinct ones).

The product of its (nonzero) digits is 57344, while the sum is 37.

The spelling of 81441744400 in words is "eighty-one billion, four hundred forty-one million, seven hundred forty-four thousand, four hundred".