81841465 has 4 divisors (see below), whose sum is σ = 98209764. Its totient is φ = 65473168.

The previous prime is 81841439. The next prime is 81841469. The reversal of 81841465 is 56414818.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 43599609 + 38241856 = 6603^2 + 6184^2 .

It is a cyclic number.

It is not a de Polignac number, because 81841465 - 2⁹ = 81840953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81841469) 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 3 ways as a sum of consecutive naturals, for example, 8184142 + ... + 8184151.

It is an arithmetic number, because the mean of its divisors is an integer number (24552441).

Almost surely, 2^81841465 is an apocalyptic number.

It is an amenable number.

81841465 is a deficient number, since it is larger than the sum of its proper divisors (16368299).

81841465 is a wasteful number, since it uses less digits than its factorization.

81841465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16368298.

The product of its digits is 30720, while the sum is 37.

The square root of 81841465 is about 9046.6272720832. The cubic root of 81841465 is about 434.1679873098.

The spelling of 81841465 in words is "eighty-one million, eight hundred forty-one thousand, four hundred sixty-five".