81281200 has 360 divisors, whose sum is σ = 276076080. Its totient is φ = 22579200.

The previous prime is 81281099. The next prime is 81281203. The reversal of 81281200 is 218218.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is not an unprimeable number, because it can be changed into a prime (81281203) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 2802786 + ... + 2802814.

It is an arithmetic number, because the mean of its divisors is an integer number (766878).

Almost surely, 2^81281200 is an apocalyptic number.

81281200 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81281200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138038040).

81281200 is an abundant number, since it is smaller than the sum of its proper divisors (194794880).

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

81281200 is a wasteful number, since it uses less digits than its factorization.

81281200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85 (or 67 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 22.

The square root of 81281200 is about 9015.6086871603. The cubic root of 81281200 is about 433.1749848785.

Adding to 81281200 its reverse (218218), we get a palindrome (81499418).

It can be divided in two parts, 812 and 81200, that multiplied together give a square (65934400 = 8120²).

The spelling of 81281200 in words is "eighty-one million, two hundred eighty-one thousand, two hundred".