81894083716225 has 81 divisors (see below), whose sum is σ = 112533994520283. Its totient is φ = 59075364480000.

The previous prime is 81894083716199. The next prime is 81894083716229. The reversal of 81894083716225 is 52261738049818.

The square root of 81894083716225 is 9049535.

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

It can be written as a sum of positive squares in 13 ways, for example, as 81879749880049 + 14333836176 = 9048743^2 + 119724^2 .

It is a de Polignac number, because none of the positive numbers 2^k-81894083716225 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81894083716229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 68188245625 + ... + 68188246825.

It is a 1-persistent number, because it is pandigital, but 2⋅81894083716225 = 163788167432450 is not.

Almost surely, 2^{81894083716225} is an apocalyptic number.

81894083716225 is the 9049535-th square number.

81894083716225 is the 4524768-th centered octagonal number.

It is an amenable number.

81894083716225 is a deficient number, since it is larger than the sum of its proper divisors (30639910804058).

81894083716225 is an equidigital number, since it uses as much as digits as its factorization.

81894083716225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2708 (or 1354 counting only the distinct ones).

The product of its (nonzero) digits is 46448640, while the sum is 64.

The spelling of 81894083716225 in words is "eighty-one trillion, eight hundred ninety-four billion, eighty-three million, seven hundred sixteen thousand, two hundred twenty-five".