81324288 has 108 divisors (see below), whose sum is σ = 239785728. Its totient is φ = 26496000.

The previous prime is 81324283. The next prime is 81324289. The reversal of 81324288 is 88242318.

It is a happy number.

It is a super-2 number, since 2×81324288² = 13227279637413888, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (81324281) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 107913 + ... + 108663.

Almost surely, 2^81324288 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 81324288, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119892864).

81324288 is an abundant number, since it is smaller than the sum of its proper divisors (158461440).

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

81324288 is a wasteful number, since it uses less digits than its factorization.

81324288 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 820 (or 803 counting only the distinct ones).

The product of its digits is 24576, while the sum is 36.

The square root of 81324288 is about 9017.9980039918. The cubic root of 81324288 is about 433.2515148617.

Adding to 81324288 its sum of digits (36), we get a square (81324324 = 9018²).

The spelling of 81324288 in words is "eighty-one million, three hundred twenty-four thousand, two hundred eighty-eight".