81223072 has 48 divisors (see below), whose sum is σ = 183375360. Its totient is φ = 34691328.

The previous prime is 81223057. The next prime is 81223073. The reversal of 81223072 is 27032218.

It is not an unprimeable number, because it can be changed into a prime (81223073) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 106918 + ... + 107674.

It is an arithmetic number, because the mean of its divisors is an integer number (3820320).

Almost surely, 2^81223072 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 81223072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91687680).

81223072 is an abundant number, since it is smaller than the sum of its proper divisors (102152288).

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

81223072 is a wasteful number, since it uses less digits than its factorization.

81223072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1253 (or 1245 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 81223072 is about 9012.3843681903. The cubic root of 81223072 is about 433.0716990007.

The spelling of 81223072 in words is "eighty-one million, two hundred twenty-three thousand, seventy-two".