81516387 has 8 divisors (see below), whose sum is σ = 110064640. Its totient is φ = 53656200.

The previous prime is 81516373. The next prime is 81516397. The reversal of 81516387 is 78361518.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81516387 - 2¹¹ = 81514339 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81516367) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 171739 + ... + 172212.

It is an arithmetic number, because the mean of its divisors is an integer number (13758080).

Almost surely, 2^81516387 is an apocalyptic number.

81516387 is a deficient number, since it is larger than the sum of its proper divisors (28548253).

81516387 is a wasteful number, since it uses less digits than its factorization.

81516387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 344033.

The product of its digits is 40320, while the sum is 39.

The square root of 81516387 is about 9028.6425890053. The cubic root of 81516387 is about 433.5923795626.

The spelling of 81516387 in words is "eighty-one million, five hundred sixteen thousand, three hundred eighty-seven".