81536784 has 60 divisors (see below), whose sum is σ = 245033424. Its totient is φ = 23295552.

The previous prime is 81536773. The next prime is 81536797. The reversal of 81536784 is 48763518.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14982 + ... + 19685.

Almost surely, 2^81536784 is an apocalyptic number.

81536784 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

81536784 is an abundant number, since it is smaller than the sum of its proper divisors (163496640).

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

81536784 is a wasteful number, since it uses less digits than its factorization.

81536784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34692 (or 34679 counting only the distinct ones).

The product of its digits is 161280, while the sum is 42.

The square root of 81536784 is about 9029.7720901471. The cubic root of 81536784 is about 433.6285409879.

The spelling of 81536784 in words is "eighty-one million, five hundred thirty-six thousand, seven hundred eighty-four".