81442161 has 12 divisors (see below), whose sum is σ = 117767988. Its totient is φ = 54235104.

The previous prime is 81442159. The next prime is 81442181. The reversal of 81442161 is 16124418.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 6533136 + 74909025 = 2556^2 + 8655^2 .

It is not a de Polignac number, because 81442161 - 2¹ = 81442159 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81442181) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4651 + ... + 13583.

It is an arithmetic number, because the mean of its divisors is an integer number (9813999).

Almost surely, 2^81442161 is an apocalyptic number.

It is an amenable number.

81442161 is a deficient number, since it is larger than the sum of its proper divisors (36325827).

81442161 is a wasteful number, since it uses less digits than its factorization.

81442161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9952 (or 9949 counting only the distinct ones).

The product of its digits is 1536, while the sum is 27.

The square root of 81442161 is about 9024.5310681497. The cubic root of 81442161 is about 433.4607348607.

Adding to 81442161 its reverse (16124418), we get a palindrome (97566579).

The spelling of 81442161 in words is "eighty-one million, four hundred forty-two thousand, one hundred sixty-one".