81840434 has 32 divisors (see below), whose sum is σ = 138862080. Its totient is φ = 35913600.

The previous prime is 81840413. The next prime is 81840439. The reversal of 81840434 is 43404818.

It is a self number, because there is not a number n which added to its sum of digits gives 81840434.

It is not an unprimeable number, because it can be changed into a prime (81840439) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 46694 + ... + 48414.

It is an arithmetic number, because the mean of its divisors is an integer number (4339440).

Almost surely, 2^81840434 is an apocalyptic number.

81840434 is a deficient number, since it is larger than the sum of its proper divisors (57021646).

81840434 is a wasteful number, since it uses less digits than its factorization.

81840434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1826.

The product of its (nonzero) digits is 12288, while the sum is 32.

The square root of 81840434 is about 9046.5702893417. The cubic root of 81840434 is about 434.1661641546.

The spelling of 81840434 in words is "eighty-one million, eight hundred forty thousand, four hundred thirty-four".