81533518 has 8 divisors (see below), whose sum is σ = 133418520. Its totient is φ = 37060680.

The previous prime is 81533509. The next prime is 81533521.

81533518 is nontrivially palindromic in base 10.

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

It is a congruent number.

It is an unprimeable number.

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, 1853013 + ... + 1853056.

It is an arithmetic number, because the mean of its divisors is an integer number (16677315).

Almost surely, 2^81533518 is an apocalyptic number.

81533518 is a deficient number, since it is larger than the sum of its proper divisors (51885002).

81533518 is a wasteful number, since it uses less digits than its factorization.

81533518 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3706082.

The product of its digits is 14400, while the sum is 34.

The square root of 81533518 is about 9029.5912421327. The cubic root of 81533518 is about 433.6227511687.

The spelling of 81533518 in words is "eighty-one million, five hundred thirty-three thousand, five hundred eighteen".