81805224 has 64 divisors (see below), whose sum is σ = 222436800. Its totient is φ = 24966144.

The previous prime is 81805219. The next prime is 81805237. The reversal of 81805224 is 42250818.

It is a junction number, because it is equal to n+sod(n) for n = 81805191 and 81805200.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 12387 + ... + 17805.

It is an arithmetic number, because the mean of its divisors is an integer number (3475575).

Almost surely, 2^81805224 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81805224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (111218400).

81805224 is an abundant number, since it is smaller than the sum of its proper divisors (140631576).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81805224 is a wasteful number, since it uses less digits than its factorization.

81805224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5482 (or 5478 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 30.

The square root of 81805224 is about 9044.6240386210. The cubic root of 81805224 is about 434.1038918249.

The spelling of 81805224 in words is "eighty-one million, eight hundred five thousand, two hundred twenty-four".