81304200 has 144 divisors (see below), whose sum is σ = 289216980. Its totient is φ = 20398080.

The previous prime is 81304187. The next prime is 81304213. The reversal of 81304200 is 240318.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81304187) and next prime (81304213).

It can be written as a sum of positive squares in 6 ways, for example, as 47361924 + 33942276 = 6882^2 + 5826^2 .

It is a super-2 number, since 2×81304200² = 13220745875280000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 29272 + ... + 31928.

Almost surely, 2^81304200 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 81304200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (144608490).

81304200 is an abundant number, since it is smaller than the sum of its proper divisors (207912780).

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

81304200 is a wasteful number, since it uses less digits than its factorization.

81304200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2696 (or 2684 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 81304200 is about 9016.8841625031. The cubic root of 81304200 is about 433.2158392829.

Adding to 81304200 its reverse (240318), we get a palindrome (81544518).

The spelling of 81304200 in words is "eighty-one million, three hundred four thousand, two hundred".