81147200 has 84 divisors (see below), whose sum is σ = 204708252. Its totient is φ = 31641600.

The previous prime is 81147173. The next prime is 81147203. The reversal of 81147200 is 274118.

It can be written as a sum of positive squares in 6 ways, for example, as 6635776 + 74511424 = 2576^2 + 8632^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81147203) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 64982 + ... + 66218.

It is an arithmetic number, because the mean of its divisors is an integer number (2437003).

Almost surely, 2^81147200 is an apocalyptic number.

81147200 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 81147200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102354126).

81147200 is an abundant number, since it is smaller than the sum of its proper divisors (123561052).

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

81147200 is a wasteful number, since it uses less digits than its factorization.

81147200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1300 (or 1285 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 23.

The square root of 81147200 is about 9008.1740658138. The cubic root of 81147200 is about 432.9368101834.

The spelling of 81147200 in words is "eighty-one million, one hundred forty-seven thousand, two hundred".