81821822 has 16 divisors (see below), whose sum is σ = 123863040. Its totient is φ = 40536312.

The previous prime is 81821813. The next prime is 81821827. The reversal of 81821822 is 22812818.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81821827) 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 7 ways as a sum of consecutive naturals, for example, 170579 + ... + 171057.

It is an arithmetic number, because the mean of its divisors is an integer number (7741440).

Almost surely, 2^81821822 is an apocalyptic number.

81821822 is a deficient number, since it is larger than the sum of its proper divisors (42041218).

81821822 is a wasteful number, since it uses less digits than its factorization.

81821822 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1087.

The product of its digits is 4096, while the sum is 32.

The square root of 81821822 is about 9045.5415537158. The cubic root of 81821822 is about 434.1332492375.

The spelling of 81821822 in words is "eighty-one million, eight hundred twenty-one thousand, eight hundred twenty-two".