81884684025 has 45 divisors (see below), whose sum is σ = 151702596991. Its totient is φ = 43664963760.

The previous prime is 81884684003. The next prime is 81884684027. The reversal of 81884684025 is 52048648818.

The square root of 81884684025 is 286155.

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

81884684025 is a `hidden beast` number, since 81 + 88 + 468 + 4 + 0 + 25 = 666.

It can be written as a sum of positive squares in only one way, i.e., 29478486249 + 52406197776 = 171693^2 + 228924^2 .

It is a tau number, because it is divible by the number of its divisors (45).

It is not a de Polignac number, because 81884684025 - 2¹³ = 81884675833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81884684027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 12873796 + ... + 12880154.

Almost surely, 2^81884684025 is an apocalyptic number.

81884684025 is the 286155-th square number.

81884684025 is the 143078-th centered octagonal number.

It is an amenable number.

81884684025 is a deficient number, since it is larger than the sum of its proper divisors (69817912966).

81884684025 is an frugal number, since it uses more digits than its factorization.

81884684025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12740 (or 6367 counting only the distinct ones).

The product of its (nonzero) digits is 3932160, while the sum is 54.

The spelling of 81884684025 in words is "eighty-one billion, eight hundred eighty-four million, six hundred eighty-four thousand, twenty-five".