81784536 has 32 divisors (see below), whose sum is σ = 204811200. Its totient is φ = 27214880.

The previous prime is 81784523. The next prime is 81784537. The reversal of 81784536 is 63548718.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81784537) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13231 + ... + 18401.

It is an arithmetic number, because the mean of its divisors is an integer number (6400350).

Almost surely, 2^81784536 is an apocalyptic number.

It is an amenable number.

81784536 is an abundant number, since it is smaller than the sum of its proper divisors (123026664).

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

81784536 is a wasteful number, since it uses less digits than its factorization.

81784536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5839 (or 5835 counting only the distinct ones).

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

The square root of 81784536 is about 9043.4803035115. The cubic root of 81784536 is about 434.0672947388.

The spelling of 81784536 in words is "eighty-one million, seven hundred eighty-four thousand, five hundred thirty-six".