81723044 has 24 divisors (see below), whose sum is σ = 159330360. Its totient is φ = 36417024.

The previous prime is 81723041. The next prime is 81723067. The reversal of 81723044 is 44032718.

It can be written as a sum of positive squares in 4 ways, for example, as 12334144 + 69388900 = 3512^2 + 8330^2 .

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a junction number, because it is equal to n+sod(n) for n = 81722998 and 81723016.

It is not an unprimeable number, because it can be changed into a prime (81723041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25589 + ... + 28604.

It is an arithmetic number, because the mean of its divisors is an integer number (6638765).

Almost surely, 2^81723044 is an apocalyptic number.

It is an amenable number.

81723044 is a deficient number, since it is larger than the sum of its proper divisors (77607316).

81723044 is a wasteful number, since it uses less digits than its factorization.

81723044 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54239 (or 54237 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 29.

The square root of 81723044 is about 9040.0798669038. The cubic root of 81723044 is about 433.9584789006.

The spelling of 81723044 in words is "eighty-one million, seven hundred twenty-three thousand, forty-four".