81764543025 has 81 divisors (see below), whose sum is σ = 161066227777. Its totient is φ = 39620539200.

The previous prime is 81764542991. The next prime is 81764543053. The reversal of 81764543025 is 52034546718.

The square root of 81764543025 is 285945.

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

81764543025 is a `hidden beast` number, since 8 + 176 + 45 + 430 + 2 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 3158327601 + 78606215424 = 56199^2 + 280368^2 .

It is a de Polignac number, because none of the positive numbers 2^k-81764543025 is a prime.

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

It is a Duffinian number.

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 80 ways as a sum of consecutive naturals, for example, 47180059 + ... + 47181791.

Almost surely, 2^81764543025 is an apocalyptic number.

81764543025 is the 285945-th square number.

81764543025 is the 142973-rd centered octagonal number.

It is an amenable number.

81764543025 is a deficient number, since it is larger than the sum of its proper divisors (79301684752).

81764543025 is a wasteful number, since it uses less digits than its factorization.

81764543025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3504 (or 1752 counting only the distinct ones).

The product of its (nonzero) digits is 806400, while the sum is 45.

The spelling of 81764543025 in words is "eighty-one billion, seven hundred sixty-four million, five hundred forty-three thousand, twenty-five".