81841784 has 16 divisors (see below), whose sum is σ = 153585720. Its totient is φ = 40885600.

The previous prime is 81841783. The next prime is 81841787. The reversal of 81841784 is 48714818.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81841783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7259 + ... + 14709.

Almost surely, 2^81841784 is an apocalyptic number.

It is an amenable number.

81841784 is a deficient number, since it is larger than the sum of its proper divisors (71743936).

81841784 is a wasteful number, since it uses less digits than its factorization.

81841784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8830 (or 8826 counting only the distinct ones).

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

The square root of 81841784 is about 9046.6449029461. The cubic root of 81841784 is about 434.1685514061.

The spelling of 81841784 in words is "eighty-one million, eight hundred forty-one thousand, seven hundred eighty-four".