81205191200 has 108 divisors (see below), whose sum is σ = 230608353402. Its totient is φ = 27841766400.

The previous prime is 81205191187. The next prime is 81205191209. The reversal of 81205191200 is 219150218.

It can be written as a sum of positive squares in 3 ways, for example, as 62002992016 + 19202199184 = 249004^2 + 138572^2 .

It is not an unprimeable number, because it can be changed into a prime (81205191209) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 996581 + ... + 1074980.

Almost surely, 2^81205191200 is an apocalyptic number.

81205191200 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81205191200 is an abundant number, since it is smaller than the sum of its proper divisors (149403162202).

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

81205191200 is a wasteful number, since it uses less digits than its factorization.

81205191200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2071595 (or 2071575 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 29.

The spelling of 81205191200 in words is "eighty-one billion, two hundred five million, one hundred ninety-one thousand, two hundred".