81831061 has 4 divisors (see below), whose sum is σ = 88125772. Its totient is φ = 75536352.

The previous prime is 81831017. The next prime is 81831067. The reversal of 81831061 is 16013818.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16013818 = 2 ⋅8006909.

It can be written as a sum of positive squares in 2 ways, for example, as 39450961 + 42380100 = 6281^2 + 6510^2 .

It is a cyclic number.

It is not a de Polignac number, because 81831061 - 2¹⁵ = 81798293 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81831067) 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, 3147336 + ... + 3147361.

It is an arithmetic number, because the mean of its divisors is an integer number (22031443).

Almost surely, 2^81831061 is an apocalyptic number.

It is an amenable number.

81831061 is a deficient number, since it is larger than the sum of its proper divisors (6294711).

81831061 is a wasteful number, since it uses less digits than its factorization.

81831061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6294710.

The product of its (nonzero) digits is 1152, while the sum is 28.

The square root of 81831061 is about 9046.0522328804. The cubic root of 81831061 is about 434.1495888318.

Adding to 81831061 its reverse (16013818), we get a palindrome (97844879).

The spelling of 81831061 in words is "eighty-one million, eight hundred thirty-one thousand, sixty-one".