81685434 has 32 divisors (see below), whose sum is σ = 169150464. Its totient is φ = 26270640.

The previous prime is 81685421. The next prime is 81685451. The reversal of 81685434 is 43458618.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 81685392 and 81685401.

It is an unprimeable number.

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, 119257 + ... + 119939.

It is an arithmetic number, because the mean of its divisors is an integer number (5285952).

Almost surely, 2^81685434 is an apocalyptic number.

81685434 is an abundant number, since it is smaller than the sum of its proper divisors (87465030).

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

81685434 is a wasteful number, since it uses less digits than its factorization.

81685434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1362.

The product of its digits is 92160, while the sum is 39.

The square root of 81685434 is about 9037.9994467802. Note that the first 3 decimals coincide. The cubic root of 81685434 is about 433.8918975874.

The spelling of 81685434 in words is "eighty-one million, six hundred eighty-five thousand, four hundred thirty-four".