81200800 has 36 divisors (see below), whose sum is σ = 198233406. Its totient is φ = 32480000.

The previous prime is 81200797. The next prime is 81200807. The reversal of 81200800 is 800218.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 62916624 + 18284176 = 7932^2 + 4276^2 .

It is not an unprimeable number, because it can be changed into a prime (81200807) 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 5 ways as a sum of consecutive naturals, for example, 49951 + ... + 51550.

Almost surely, 2^81200800 is an apocalyptic number.

81200800 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81200800 is an abundant number, since it is smaller than the sum of its proper divisors (117032606).

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

81200800 is a wasteful number, since it uses less digits than its factorization.

81200800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101521 (or 101508 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 19.

The square root of 81200800 is about 9011.1486504219. The cubic root of 81200800 is about 433.0321115026.

The spelling of 81200800 in words is "eighty-one million, two hundred thousand, eight hundred".