81784481 has 8 divisors (see below), whose sum is σ = 85791744. Its totient is φ = 77814880.

The previous prime is 81784477. The next prime is 81784499. The reversal of 81784481 is 18448718.

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

It is a cyclic number.

It is not a de Polignac number, because 81784481 - 2² = 81784477 is a prime.

It is a super-2 number, since 2×81784481² = 13377402664878722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81784081) 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, 4916 + ... + 13701.

It is an arithmetic number, because the mean of its divisors is an integer number (10723968).

Almost surely, 2^81784481 is an apocalyptic number.

It is an amenable number.

81784481 is a deficient number, since it is larger than the sum of its proper divisors (4007263).

81784481 is a wasteful number, since it uses less digits than its factorization.

81784481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18831.

The product of its digits is 57344, while the sum is 41.

The square root of 81784481 is about 9043.4772626463. The cubic root of 81784481 is about 434.0671974356.

The spelling of 81784481 in words is "eighty-one million, seven hundred eighty-four thousand, four hundred eighty-one".