81536331 has 8 divisors (see below), whose sum is σ = 111366864. Its totient is φ = 53031680.

The previous prime is 81536327. The next prime is 81536339. The reversal of 81536331 is 13363518.

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

It is a cyclic number.

It is not a de Polignac number, because 81536331 - 2² = 81536327 is a prime.

It is a super-2 number, since 2×81536331² = 13296346545883122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81536339) 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 7 ways as a sum of consecutive naturals, for example, 331326 + ... + 331571.

It is an arithmetic number, because the mean of its divisors is an integer number (13920858).

Almost surely, 2^81536331 is an apocalyptic number.

81536331 is a deficient number, since it is larger than the sum of its proper divisors (29830533).

81536331 is a wasteful number, since it uses less digits than its factorization.

81536331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 662941.

The product of its digits is 6480, while the sum is 30.

The square root of 81536331 is about 9029.7470064227. The cubic root of 81536331 is about 433.6277379389.

Adding to 81536331 its reverse (13363518), we get a palindrome (94899849).

The spelling of 81536331 in words is "eighty-one million, five hundred thirty-six thousand, three hundred thirty-one".