81255782916 has 243 divisors, whose sum is σ = 263052641397. Its totient is φ = 21071191680.

The previous prime is 81255782857. The next prime is 81255782939. The reversal of 81255782916 is 61928755218.

The square root of 81255782916 is 285054.

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

81255782916 is a `hidden beast` number, since 8 + 1 + 2 + 557 + 82 + 9 + 1 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 2353220100 + 78902562816 = 48510^2 + 280896^2 .

Its product of digits (2419200) is a multiple of the sum of its prime divisors (640).

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, 131694640 + ... + 131695256.

Almost surely, 2^81255782916 is an apocalyptic number.

81255782916 is the 285054-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81255782916

81255782916 is an abundant number, since it is smaller than the sum of its proper divisors (181796858481).

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

81255782916 is a wasteful number, since it uses less digits than its factorization.

81255782916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1280 (or 640 counting only the distinct ones).

The product of its digits is 2419200, while the sum is 54.

The spelling of 81255782916 in words is "eighty-one billion, two hundred fifty-five million, seven hundred eighty-two thousand, nine hundred sixteen".