81547842 has 8 divisors (see below), whose sum is σ = 163095696. Its totient is φ = 27182612.

The previous prime is 81547819. The next prime is 81547847. The reversal of 81547842 is 24874518.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

81547842 is an admirable number.

It is a self number, because there is not a number n which added to its sum of digits gives 81547842.

It is not an unprimeable number, because it can be changed into a prime (81547847) 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 3 ways as a sum of consecutive naturals, for example, 6795648 + ... + 6795659.

It is an arithmetic number, because the mean of its divisors is an integer number (20386962).

Almost surely, 2^81547842 is an apocalyptic number.

81547842 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

81547842 is a wasteful number, since it uses less digits than its factorization.

81547842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13591312.

The product of its digits is 71680, while the sum is 39.

The square root of 81547842 is about 9030.3843772012. The cubic root of 81547842 is about 433.6481429696.

The spelling of 81547842 in words is "eighty-one million, five hundred forty-seven thousand, eight hundred forty-two".