81784863 has 16 divisors (see below), whose sum is σ = 121804800. Its totient is φ = 54234360.

The previous prime is 81784861. The next prime is 81784889. The reversal of 81784863 is 36848718.

It is not a de Polignac number, because 81784863 - 2¹ = 81784861 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81784861) 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 15 ways as a sum of consecutive naturals, for example, 2773 + ... + 13086.

It is an arithmetic number, because the mean of its divisors is an integer number (7612800).

Almost surely, 2^81784863 is an apocalyptic number.

81784863 is a deficient number, since it is larger than the sum of its proper divisors (40019937).

81784863 is a wasteful number, since it uses less digits than its factorization.

81784863 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16059 (or 16053 counting only the distinct ones).

The product of its digits is 258048, while the sum is 45.

The square root of 81784863 is about 9043.4983828162. The cubic root of 81784863 is about 434.0678732501.

It can be divided in two parts, 8178 and 4863, that added together give a triangular number (13041 = T₁₆₁).

The spelling of 81784863 in words is "eighty-one million, seven hundred eighty-four thousand, eight hundred sixty-three".